FOR PUBLICATION



### UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT

O L E A N W H O L E S AL E G RO C E R Y C O O P E R A T I V E , I N C

. , B EV E R

L Y Y O U N GB L O O D , P A C I F I C G RO S E R V I C E , I N C ., DBA Pitco Foods, C AP I T O L H I L L S UP E R M AR K E T , L O U I S E A

N N D A V I S M A T T H E W S , J AME S WAL N UM , C O L I

N M O O R E , J E N N I F E R A. N E L S ON , E L I Z AB E T H D A

V I S

- B E RG , L A

UR A C H I L D S ; N A

N C Y S T I L L E R ; B ON

N I E V A ND E R L A A N ; KR I S T I N M I L L I C A

N ; T R E P C O I MP O R

T S A ND D I S T R I B U T I ON , L T D .; J I

NK Y O U N G M O O N ; C O R E Y N O R R I S ; C L AR

I S S A S I M O N ; A MB E R S AR

T O R I ; N I G E L WA R R E N ; A M Y J O S E P H ; M I C HAE L J UE T T E N ; C A R L A L O W N ; T R U YE N T ON -V U O

N G , AKA David Ton; A-1 D I N E R ; D W

A Y N E KE N N E D Y ; R I C K M U S GR A V E ; D U T C H V I L L A G E RE S T A UR A N T ; L I S A B UR

R ; L A R R Y D E M ON A C O ; M I C HAE L B UF F ; E L L E N P I N T O ; R O B B Y RE E D ; B L A I R H Y S N I ; D E N N I S Y E L V I

N G T ON ; K

A T HY D UR A ND G O R E ; T H O M

A S E. W I L L O U GH B Y III; R O B E R T F R A G O S O ; S AM UE L S E I D E

NB URG ; J A

N E L L E A L B AR E L L O ; M I C HAE L C O F F E Y ; J A S ON W I L S ON ; J AD E C A N T E R B U R Y ; No. 19-56514

D.C. No. 3:15-m d-02670- DMS-MDD

OPINION2 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

N A Y A L I D AD ; G AL Y

N A A ND R U S Y S HY N ; R O B E R

T B E N J AM I N ; B AR B AR A B UE N N I N G ; D A N I E L L E G R E E NB E RG ; S H E R

Y L H AL E Y ; L I S A H AL L ; T Y

A H U GH E S ; M AR

I S S A J A C O B U S ; G A

B R I E L L E K UR D T ; E R I C A P R UE S S ; S E T H S AL E

N GE R ; H ARO L D S T AF F O R

D ; C AR L L E S H E R ; S AR

AH M E T I V I E R S C HAD T ; G R E G S T E AR

N S ; K AR R E N F AB I A N ; M E L I S S A B O W M A N ; V I V E K D R

A V I D ; J O D Y C O O P E R ; D A

N I E L L E J O H

N S ON ; H E R B E R T H. KL I E G E R

M A N ; B E T H M I L L I N E R ; L I Z A M I L L I

N E R ; J E F F R

E Y P O T V I N ; S T E P HA

N I E G I P S ON ; B AR B AR A L YB ARG E R ; S C O T T A

. C AL D WE L L ; R

AM ON R U I Z ; T HYME C AF E & M AR

K E T , I N C .; H A

R V E S T E R S E N T E R P R I S E S , LLC; A F F I L I A T E D F O O D S , I N C .; P I G G L Y W I G G LY A L AB AM

A D I S T R I B U T I N G C O

. , I N C .; E L I Z AB E T H T WI T C H E L L ; T I N A G R A N T ; J O H N T R E N T ; B R I A N L E V Y ; L O U I S E A D A

M S ; M ARC B LUM S T E I N ; J E S S I C A B R

E I T B A C H ; S AL L Y C R NKO V I C H ; P A

UL B E RGE R ; S T E R L I N G K I N G ; E V E L Y

N O L I V E ; B AR B AR A B LUM S T E I

N ; M A R Y H UD S ON ; D I A

N A M E Y ; A S S O C I A T E D G RO C E R S O F N E W E N G L A ND , I N C .; N O R T H C E N T R AL D I S T R

I B U T O R S , L L C ; C A S H W

A D I S T R I B U T I N G C O

. O F KE AR N E Y , I N C .; U R

M S T O R E S , I N C .; W E S T E R

N F AM I L Y F O O D S , I N C .;3

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

A S S O C I A T E D F O O D S T O R E S , I N C .; G I A N T E A GL E , I N C

. ; M C L A N E C O MP A N Y , I N C

. ; M E AD O W

B RO O K M E A T C O MP A

N Y , I N C .; A S S O C I A T E D G RO C E R S , I N C .; B I L O H O L D I N G , LLC; W I

N N D I X I E S T O R

E S , I N C .; J A NE Y M A C H I

N ; D E B R

A L. D AM S K

E ; KE N D U N L AP ; B AR

B AR A E. O L S ON ; J O H N P E Y C HAL ; V I R

G I N I A R AK I P I ; A D AM B UE H R

E N S ; C A S E Y C H R I S T E N S E N ; S C O T T D E

N N I S ; B R I A N D E P P E R S C H M I D T ; A M Y E. WA T E R M A N ; C E N T R AL G RO C E R S , I N C .; A S S O C I A T E D G R O C E R S O F F L O R I D A , I N C .; B E

N J AM I N F O O D S LLC; A L B E R

T S ON S C O MP A

N I E S LLC; H.E. B U T T G RO C E R Y C O MP A N Y ; H Y VE E , I N C .; T H E KRO GE R C O .; L E S G O P E R S ON AL C H E F LLC; K

A T HY V A

N G E ME R

T ; E D Y Y E E ; S U

ND E D A N I E L S ; C H R I S T O P H E R T O D D ; P UB L I X S UP E R M AR K E T S , I N C .; WAK

E F E R N F O O D C O R P .; R O B E R

T S K AF F ; W E GM

A N S F O O D M AR

K E T S , I N C .; J UL I E W I E S E ; M E I J E R D I S T R

I B U T I O N , I N C .; D A

N I E L Z WI R L E I N ; M E I J E R , I N C

. ; S UP E R V ALU I N C .; J O H

N G RO S S & C O MP A

N Y ; S UP E R S T O R

E I ND U S T R

I E S ; W L E E F L O WE R S & C O I N C .; F AM I LY D O L L A R S E R VI C E S , LLC; A M

Y J A C K S ON ; F AM I L Y D O L LAR S T O R E S , I N C .; K A T H E R I N E M C M

AH ON ; D O L L A R T R E E D I S T R

I B U T I ON , I N C .;4 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

J ON A T H A N R I Z Z O ; G R

E E NB R I E R I N T E R N A T I ON AL , I N C .; J O E L Y

N A A. S A N A G U S T I N ; A L E X L E E , I N C .; RE B E C C A L E E S I M O E N S ; B I G Y F O O D S , I N C .; D A

VI D T ON ; K

V A T F O O D S T O R

E S , I N C ., DBA Food City; A F F I L I A T E D F O O D S M I D W E S T C O O P E R A T I V E , I N C

. ; M E RC HA N T S D I S T R I B U T O R S , LLC; B RO O K S H I R E B RO T H E R S , I N C .; S C H N U C K M AR K E T S , I N C .; B RO O K S H I R E G RO C E R

Y C O MP A

N Y ; K M A R T C O R P O R A T I ON ; C E R

T C O , I N C .; R U S H I N G O L D , LLC, DBA The Gold Rush; U N I F I E D G R

O C E R S , I N C .; T ARG E T C O R

P O R A T I ON ; S I M ON

H I ND I , LLC; Fareway Stores, Inc.;Moran Foods, LLC, DBA Save-ALot; W O O D M

A N ’ S F O O D M AR

K E T , I N C .; D O L L A

R G E N E R AL C O R P O R A T I ON ; S AM ’ S E A S T , I N C .; D O L G E N C O R P , LLC; S AM ’ S W E S T , I N C .; KR

A S D AL E F O O D S , I N C .; WAL M AR T S T O R E S E A S T , LLC; CVS P HAR M A C Y , I N C .; WAL M

AR T S T O R E S E A S T , LP; B A S HA S ’ I N C .; WAL

- M AR T S T O R E S T EX A S , LLC; M ARC G L A S S M

A N , I N C .; WAL

- M

A R T S T O R E S , I N C .; 99 C E

N T S O N LY S T O R E S ; J E S S I C A B AR

T L I N G ; A H O L D U.S.A., I N C .; G A

Y B I R NB A UM ; D E L HAI Z E A ME R

I C A , L LC; S AL L Y B R E D B E RG ; A S S O C I A T E D W H O L E S AL E G RO C E R S , I N C .; K I M5

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

C R A I G ; M A Q U O K

E T A C AR

E C E N T E R ; G L O R I A E ME R

Y ; E R B E R T & G E R B E R T ’ S , I N C

. ; A

N A G AB R I E LA F E L I X G A

RC I A ; J A

N E T M A C H E

N ; J O H N F R I C K ; P A I N T E D P L A T E C A T E R I N G ; K A T H L E E N G AR N E R ; R O B E R T E T T E N ; A ND R E W G O R M A N ; G RO U C H O ’ S D E L I O F F I V E P O I N T S , LLC; E D G

AR D O G U T I E R

R E Z ; G RO U C H O ’ S D E L I O F R AL E I GH ; Z E ND A J O H

N S T ON ; S A

ND E E ’ S C A T E R I N G ; S T E V E

N KR A T K Y ; C ONF E T T I ’ S I C E C R

E A M S H O P P E ; K A T HY L I N G N O F S K I ; E ND P A

Y E R P L A I N T I F F S ; L A

UR A M ON T O Y

A ; K I R S T E N P E C K ; J O H

N P E L S ; V AL E R

I E P E T E R S ; E L I Z AB E T H P E R RON ; A UD R

A R I C K M A N ; E R I C A C. R O D R

I G UE Z , Plaintiffs-Appellees
,

and

J E S S I C A D E C K

E R , J O S E P H A. L A N G S T ON , S A

ND R A P O WE R S , G R A ND S UP E RC E

N T E R , I N C ., T H E C H E RO K

E E N A T I ON , US F O O D S , I N C ., S Y S C O C O R

P O R A T I ON , G LAD Y S , LLC, S P A

R T A N N A S H C O M

P A N Y , B R Y A N A N T H ON Y RE O , Plaintiffs
,

v

.6 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

B UMB L E B E E F O O D S LLC; S T AR K I S T C O .; D ON GWON I ND U S T R I E S C O ., L T D ., Defendants-Appellants
,

and

K I N G O S C AR , I N C .; T H

AI U N I O N F RO Z E N P RO D U C T S PCL; D E L M ON T E F O O D S C O M

P A N Y ; T R I M AR I N E I N T E R

N A T I ON AL , I N C .; D ON GW ON E N T E R

P R I S E S ; D E L M ON T E C O R

P .; C HR I S T O P H E R D. L I S C H E W S K

I ; L I ON C A

P I TAL (A ME R I C A S ), I N C

. ; B I G C A T C H C A YM A N LP, AKA Lion/Big Catch Caym an LP; F R

A N C I S T E N T E R P R I S E S ; G L O W

F I S C H H O S P I T AL I TY ; T HA I U N I ON N O R

T H A ME R I C A , I N C ., D efendants.7

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
Appeal from

the United States District Court for the Southern District of California Dana M. Sabraw, Chief District Judge, Presiding

A rgued and Subm itted En Banc Septem ber 22, 2021 Pasadena, California

Filed April 8, 2022

Before: Andrew J. Kleinfeld, Sidney R. Thom as, Susan P. Graber, W illiamA. Fletcher, Ronald M. Gould, Richard A. Paez, Consuelo M. Callahan, Sandra S. Ikuta, Paul J. W atford, Michelle T. Friedland and Kenneth K. Lee,

Circuit Judges.

O pinion by Judge Ikuta; Dissent by Judge Lee8 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

SUMMARY *

Antitrust / Class Certification

The en banc court f

iled an opinion affirm ing the d i s t r i ct court’s order certifying three sub classes of tuna purchasers who alleged that the suppliers violated federal and st a te antitrust laws. The en banc court h eld that the dis t rict court did not abuse its discretion in concluding that the purchasers’ statistical reg ressio n m o d e l, along with other expert evidence,

was capable of showing that a price-fixing conspiracy caused class-wide antitrust im

pact, thus satisfying one of the prerequisites f

or bringing a class action under Federal Rule o f Civil Procedure 23(b)(3).

To take advantage of Rule 23’s procedure for aggregating claim s, plainti ffs m

ust m ake two showings. First, under Rule 2 3(a), they m

ust establish t h a t “ there are questions o f law or f act comm on to the class,” as well as dem onstrate

num erosity, typicality, and adequacy of representation. Second, the plaintiffs m

u st show that the class fits into o ne o f three categories under Rule 23(b). To qualify for th e third category, Rule 23(b)(3) the d i s trict court m ust find that “questions o f l a w or fact comm o n to class m em bers predom i n ate over any q uestions affecting only individual

m em bers.”

J o ining o ther circuits, the en banc court held tha t plaintiffs m

ust prove by a preponderance of the evidence the facts necessary to carry the burd en of establishing that the

* This summ ary constitutes no part of the opinion of the court. It h as been prepared by court staff for the convenience of the reader.9

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
prerequisites of Rule 23 are satisfied. The en b anc court held that to prove a comm on question of law o r fact that relates to

a central issue in an antitrust class action, plaintiffs m ust establis h t h a t essential elem ents of the cause of action, such

a s the existence of an antitrust violation or antitrust im pact , are capable o f being established t h r o ug h a comm o n b ody o f evidence, applicable to the whole class.

The en b anc court h eld that in m aking the d eterm inations
necessary to find that the p rerequi s ites of Rule 23(b)(3) are satisfied, the distr ict court m ay weigh conflicting expert testim ony and resolve expert dispu t e s. In determ ining whether the “comm on question” prerequisite is m e t , the district court is lim ited to resolving whether the evidence establishes that a comm on question is capable of class-wide resolution, not whether the evidence in fact establishes that plaintiffs would win at trial. The di s t r i c t court m ust also

res o l v e disputes about historical facts if necessary to determi n e whether the plaintiffs’ evidence is capable o f

res o l v i n g a comm on issue central to the plaintiffs’ claim s. Th e refore, the district court cannot decline certification

m erely because it co n sid ers p l aintiffs’ evidence relating to the

comm on q

uestion to be unpersuasive and unlikely to succeed in carrying the plaintiffs’ burden o f proof on that issue. Nor can a district court decline to certify a class that will require determ ination of som e indi v i dualized questions at trial, so long as such questions do not predom inate over the comm on questions.

The en banc court held th at wh e n in d iv idualized questions relate to the injury status of class m em bers, Rule 2 3(b ) ( 3 ) requires that the court dete r mi ne whether individualized inquiries about such m atters would pr edom inate over

comm on questions. Therefore, the en banc court rejected the10 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

argum ent that Rule 23 does not p erm it the certification of a class that potentially includes m ore than a de m inim is num ber of uninjured class m em

bers.

Beginning with the “DPP” class of direct pur c h a s ers o f the tuna suppliers’ products, such as nationwide retailers and regional grocery stores, the p anel held that in o rder to prevail

on their antitrust claim
, the DPP class was required to prove that the tuna suppliers engaged in a conspiracy ( a n a n titrust violation), which resulted in antit ru st im pact in the form o f higher prices paid by each m em ber of the class, which in turn led to m easurable d am ages. The question whether each

m em ber of the D PP class suffered anti t rust im p act was central to the validity of each of the DPP claim s. The central questions on appeal we re whether the expert evidence presented by the DPPs w as capable of resolving this issue “in

one stro k e, ” an d wh eth er th is co m m o n q u estion predom inated over any individualized inquiry.

The en banc court concluded that the district court did not abuse its di scretion in certifying the class. The DPPs relied

on the ex p e r t testim ony and report of Dr. Russell Mangum
, whose findings about the tuna market and tuna suppliers’ collusive behavior, pricing correlation test, regression m odel, and robustness checks confirm ed his theory that th e pricefixing c o n spiracy resulted in substantial price im p acts, and that the im

p act was comm on to the DPPs during the collusion period. The en banc court concluded that the d i s t ri c t c ourt did not m ake any legal or factual error when, in considering whether the DPPs ’ evidence w as capable of establishing antitrust im

p act for the class as a whole, the district court reviewed Dr. Mangum ’s expert testim ony and r ep o r t, the rebu tt a l testim ony and report by Dr. John Johnson, and Dr. Man g um ’s reply, and then addressed the p arties’ disputes.11

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

The district court thus properly concluded that Dr. Mangum ’s pooled r egression m odel, along with other evidence, was capable of answering the question whether there was antitrust im pact due to the collusion o n a class-wide basis, thus satisfying this prerequisite of Rule 23(b)(3).

The en banc court held that the district court did n ot abuse its disc r et i o n in determ ining that the evidence presented by the DPPs proved: (1) that the elem ent of antitrust im pact was capabl e o f being established class-wide through comm on proof, and (2) that this comm o n question predom inated over individual question s

. The en banc court rejected any categorical argu ment that a pooled regression m odel cannot control fo r variables relating to the individual d ifferences

am ong class m em

bers. The en banc court also rejecte d the

a rgum ent that, in this case, the m odel’s output could n o t p lausibly serve as comm on evidence for all class me mb e rs given the individual differences am ong those class m em bers. The en banc court held that the d i s t rict court did not err by failing to resolve a dispute between the parties as to whether 28 percent of the class did not suffer antitrust im p act. Rather, the district court fulfilled its obligation to resolve the disputes raised by the p arties in order to satisfy itself that the evidence
proves the prerequisites for R u le 2 3(b)(3), which was that the

e v i dence was capable of showing that the DPPs suffered antitrust impact on a class-wide basis.

The en b anc court held that the district court also did not abuse it s discretion in determ ining that the evidence presented by the “CFP” class of indirect purchasers of bulksized tuna products and the “EPP” class of individual end purchasers was capable of proving th e elem ent o f antitrust im pact under California’s Cartwright Act, thus satisfying the prerequisites of Rule 23(b)(3).12 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
Dissenting, Judge Lee, joined by Judge Kleinfeld, wrote that the m ajority opinion allowed the district court to certify

a class, ev e n though potentially about one out o f three class

m em bers suffered no injury. Judge Lee wr o t e that if defendants’ econom etrician expert was correct that alm o st a third of the class m em

bers m ay not have suffered injury, then plaintiffs did not show the predom in a n c e o f comm on issues under Rule 23(b)

. He wrote that because class action cases alm ost always settle once a court cer t ifi e s a class, a district
court mu s t serve as a gatekeeper to resolve key issues im plicating Rule 23 requirem ents, including wh e ther too

m any p utative class m em b ers suffered no injury, at the class certificatio n stage. F urther, the m ajority’s rejection of a de

m inim is rule, unde r which the num ber of uninjured class

m em bers should be de m inim is, created a circuit split.

C OUNSEL

Gregory G. G arre (argued), Sam ir Deger

- Se n, and Shannon Gramm el, Latham & W atkins LLP, W ashington, D.C.; Christopher S. Yates, Belinda S. Lee, and Ashley M. Bauer, Latha m & W atkins LLP, San Francisco, California; for Defendants-Appellants StarKist C o

. and Dongwon Industries Co. Ltd.

Christopher L. Lebsock (argued), Michael P. Lehm ann, Bon ny E. Sweeney, and S am antha J. Stein, Hausfeld LLP, Sa n Francisco, California, for Plaintiffs-Appellees Direc t Purchaser Plaintiff Class.

Jonathan W

. Cuneo (argued), Joel Davidow, and Bl a ine Finley, Cuneo Gilbert & Laduca LLP, W ashington, D.C., for13

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
Plaintiffs-Appellees Comm ercial Food Preparer Plainti ff Class.

Thom as H. Burt (argued), W o lf Haldenstein Adler F reem an & Herz LLP, New York, New York; Betsy C. M anifold, Rachele R

. B yrd, Marisa C. Livesay, and Brittany N

. DeJong, W olf Haldenstein Adler Freem an & He r z LLP, San Diego, California; for Plaintiffs-Appellees End Payer Plaintiff Class.

Corbin K. Barthold and Cory L. Andrews, W ashington, D.C., for Am icus Curiae W ashington Legal Foundation.

Ashley C. Parrish and Joshua N

. Mitchell, King & Spalding LLP, W ashington, D.C.; Steven P

. Lehotsky, Jonan D. Urick, Daryl Joseffer, and J e nnifer B. Dickey, United States Cham ber Litigation Center; Anne M. Voi g t s , Quyen L. Ta, and Suzanne E. Nero, King & Spalding LLP, San Francisco, Cali fo rnia; K erry Perigoe, K ing & Spalding LLP, Los Angele s , California; Christopher A

. Mohr, Software & Inf o rm atio n I n d

u stry A ssociation, W ashington, D .C.; Jeanine Poltronieri, Internet A ssociation, W ashington, D.C.; for Am ici Curiae C ham

ber of C o mm erce of the United States o f Am erica, Software Inform ation Industry Association, a n d Internet Association.

Randy M. Stutz, Am erican A ntitrust Institute, Wa s hi n gton, D.C.; Professor Joshua P. Davis, University of San Francisco School o f Law, S an F rancisco, California; Ellen Meriwether, C a f f e r t y C l o b e s M e r i w e t h e r & S p r e n g a l
, M e d i a , Pennsylvania; for Am icus Curiae Am eric a n Antitrust Institute.14 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

Scott L. Nelson and Alliso n M. Zieve, Public Citizen Li t igation G roup, W ashington, D.C., for Am icus Curi a e Public Citizen Inc.

Jocelyn D. Larkin, Lindsay Nako, and David S. Na h mias, Im pact Fund, Berkeley, California, for A m ici Curiae Im pact Fund, B et Tzedek, California Rural Legal Assistance Foundation, Centro Legal de la R aza, Legal Aid at W ork, and Public Counsel.

Karla Gilbride, W ashington, D.C., as and for Am icus Curiae Public Justice P.C.

De b o r ah A

. Elm an and Chad Holtzm an, Garwin Gerstein & Fisher LLP, New Y ork, New Y o r k; Wa rren T. B urns and Kyle K. Oxford, B urns Charest LLP, Dallas, Texas; R obert S. Kitchenoff, President; Lin Y. Ch an, Vice President, Comm ittee to S upport the A ntitrust Laws, W ashington, D.C.; for Am icus Curiae Comm ittee to Support the Antitrust Laws.

Jonathan F. Cohn, Josh ua J. Fougere, and Jacquelyn E. Fradette, Sidley Austin LLP, W ashington, D.C., for Am icus Curiae Consum er Healthcare Products Association.15

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

OPINION

IKUTA, Circuit Judge:

The prim ary suppliers of packaged tuna in the United States appeal the district court’s order certifying three classes of tuna purchasers wh o allege the suppliers violated federal and state antitrust laws. T he m ain issue on appeal is whether the purchasers’ statistical regression m odel, along with other expert evidence, is cap able of showing that a price-fixing conspiracy caused class-wide antitrust im pact, thus satisfying

one of the prerequisites for bringing a class action under Rule 23(b)(3) of the Federal Rules of Civil P rocedure. Because the district court did not abuse its discretion in concluding that Rule 23(b)(3) was satisfied, we affirm

.

I

Bum ble Bee, 1 St arKist, and Chicken of the Sea (COSI), and their parent com

panies are the largest suppliers o f packaged tuna in the U nited States (referred to collectively as the “Tuna Suppliers”). Their products include packaged tuna sold to direct purchasers like Costco and W alm art, and foodservice-size tuna products sold to var i o us distributors for resale. Together, the Tuna Suppliers sell over 80 percent o f the packaged tuna in the country.

In late 2015, the United States Departm ent o f Justice (DOJ) opened an in v e s t i gation into the packaged tuna

1 As a r esult of Appellant Bum ble Bee Foods LLC’s b ankruptcy proceeding, appellate proceedings against Bum ble Bee Foods have been held in abeyance due to the autom atic stay im posed by 11 U.S.C. § 362. Dkt. No. 51.16 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
industry for violations of f ederal antit ru st law. The DOJ investigation uncovered ev i de nce of a price-fixing schem e

am ong the Tuna Sup pliers, which led the DOJ to enter

m ultiple indictm ents alleging a cr imi n al conspiracy to f ix prices of canned tuna for the period fr o m ap proxim ately Novem ber 2011 through Decem b er 2 013. Bu mb l e Bee, StarKist, and three tuna industry executives pleaded guilty to the conspiracy. Bum

b le Bee’s form er C EO was convicted by

a jury of a conspiracy to fix prices. 2 COSI cooperated with the DOJ and adm i t t ed to price f ixing in exchange for leniency.

A num ber of purchasers of the T una Suppliers’ p roducts (referred to collectively as the “Tuna Purchasers” ) filed putative cla s s actions against the Tuna Suppliers alleging violations of various federal and state antitrus t l a ws. The Tuna Purchasers alleged that the Tuna Suppliers engaged in

a conspiracy from Novem b er 2010 through at least D ecem ber 31, 2 0 1 6 to fix prices of tuna, along with other collusive activities in furtherance of th e p rice-fixing conspiracy. The Tuna Purchasers allege d t h at they were dam aged by the

2 Pl e a Ag reem ent, United States v. Bumble Bee Foods LLC
, No. 3:17-cr-00249-EMC (N.D. Cal. Aug. 2, 2017), ECF No. 32; Plea Agreem ent, U

nited States v. Worsham
, No. 3:16-cr-00535-EMC (N

. D

. Cal. Mar. 1 5, 2017), ECF No. 1 4; Plea Agreem ent, United States v. Cameron
, No. 3:16-cr-00501-EMC (N.D. Cal. J a n

. 25, 2017), E CF No. 18; Plea Agreem ent, United States v. Hodge
, No. 3 :17-cr-00297-EMC (N.D. Cal. June 28, 2017), ECF No. 13; P lea Agreem ent, United States v. StarKist Co.
, No. 3:18-cr-00513-EMC (N.D. Cal. Nov. 14
, 2 0 1 8 ), ECF No. 24.17

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. B UM B L E B E E F O O D S
conspiracy because they paid supra-comp etitive prices for the Tuna Suppliers’ products. 3

Th e Tuna Purchasers’ actions were consolidated i n a

m ultidistrict litigation pretrial proc e e ding in the Southern District of California. The Tuna P urchasers consist of three putative subclasse s : ( i ) direct purchasers of the Tuna Suppliers’ products, such as nationwide retailers and regional
gr ocery stores, who purchased packaged tuna between June 1, 2011 and July 1
, 2015 (the “DPPs”); (ii) indirect purchasers of the Tuna Suppliers’ products who bought bulksized tuna products between June 2011 and Decem ber 20 16 for prepared f

ood or resale (the “CFPs”); and (iii) individual end purc h a sers who bought the Tuna Suppliers’ p roducts between June 1, 2011 and July 1, 2015 fo r p ersonal

consum ption (the “EPPs”).

In 2 0 1 8
, the Tuna Purchasers m oved to certify the three subclasses under Rule 2 3 o f the F ederal Rules of Civil Procedur e t o proceed as a class action. See Fed. R. Civ. P. 23(a), (b)(3). To d em onstrate class-wide antitrust im pact, each subclass proffered evidence from a different econom ist, each of whom em

ployed substantially sim ilar m ethodologies,
to show that each m em

ber of the subclass e s h ad p aid an overcharge caused by the Tuna Suppliers’ conspiracy. The Tuna S uppliers contested t h i s expert evidence through their

own econom ists. The distr i ct court held a three-day evidentiary h earing o n the certification m ot ion, and heard

3 Supra-com

petitive prices are those prices elevated “above

com p etitive l evels” by a m arket participant w ho “exercise[s] [its] m arket power” to do so. ABA Section of Antitrust Law
, Ec o nometrics: Legal, Practical, and Technical Issues 2 52 (2d ed. 2014) (“ Econometrics ”).18 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

substantial testim ony f

rom each expert w itness. In July 2019, the district court certified all three subclasses.

The T una S uppliers tim ely ap pe aled, and a panel of this
court vacated the district court’s o rder and rem anded. See Olean Wholesale Grocery Coop., Inc. v. Bumble Be e Foods LLC
, 993 F .3d 774, 794 (9th Cir. 20 2 1 )
, reh’g en banc granted
, 5 F.4th 950 (9th Ci r

. 2 0 2 1). W e took the case en b an c to consider whether the district court erred in findi n g that each subclass satisfied the requirem ent that “questions o f law or fact comm on to class m em bers predom inate over any questions affecting only individual m em bers.” Fed. R. Civ. P. 23(b)(3).

W e have jurisdiction under 28 U.S.C. § 1 2 9 2 (e) and Rule 23(f) of the Federal Rules of Civ i l Pr o c e dure. W e review t he d ecision to certify a class and “any particular underl y ing Rule 23 determ ination involving a discretionary determ ination ” fo r an abuse o f discretion. Y okoyama v. Mi dl a n d Na t’l Life Ins. C o

. , 594 F.3d 1087, 1091 (9th Cir. 2010). W e review the district court’s determ ination o f underlying legal questions de novo, id.
, and its determ ination of underlyi n g factual questions for clear error, see Ruiz Torres v. Mercer Canyons Inc.
, 835 F.3d 1125, 1132 (9th Cir. 2 0 16). The S uprem e Court has indicated that a court’s determ ination regarding what a statistical regression m odel

m ay prove o r is capable of proving is not a question o f fact,

even though there m ay be disputed issues of fact raised by “the data contained within an econom etric m odel.” Comcast Corp. v. Behrend
, 569 U.S. 27, 36 n.5 (2013). Accordingly, we review the district court’s determ ination that a statistical regression m odel, along with other expert ev i d e n ce, is capable of showing class-wide im pact, thus satisfying one o f the prerequisites of Rule 23(b)(3) of the Federal Rules o f19

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

Ci v i l Procedure, for an abuse of discretion. See Yokoyama
, 594 F.3d at 1091.

II

A

Rule 23 provides a procedural m e c hanism for “a federal
court to adjudicate claim s of m u ltiple parties at once, instead of in separate suits.” Shady Grove O rthopedic Assocs., P

. A.

v. Allstate Ins. Co.
, 5 5 9 U.S. 3 93, 408 (2010). As a claim saggrega t i ng device, Rule 23 “leaves the parties’ legal rights and duties intact a n d t h e rules o f decision unchanged,” id.
, and it does not affect the substance of the claim s or plaintiffs’ burden of proof, see 28 U.S.C. § 2072(b).

To take advantage of Rule 23’s procedure for aggregating claim s, pl a i ntiffs m

ust m ake two showings. First, the plaintiffs m

u st establish “ther e a r e questions of law or fact

comm on to th e c l a ss,” as well as dem onstrate num erosity, typicality an d adequacy o f representation. 4 Fed. R. Civ. P.

4 Rule 23(a) provides:

Prerequisites. One o r m ore m em bers of a class m ay sue

o r be sued as r epresentative parties on behalf o f a l l

m em bers only if:

(1) the class is so num erous that joinder o f all

m em bers is im practicable;

(2) there are questions of l aw or fact c o mm on to the class;20 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
23(a). A comm on question “must be of such a nature that it is capable of classwide resolution—which m eans t h at determ ination of its truth or falsity will resolve an issue that is central to the v alidity of each one o f t h e claim s in o ne stroke.” Wal-Mart Stores, Inc. v. Du k e s , 564 U.S. 338, 350 (2011). By contrast, an individua l question is one where

m em bers of a proposed class will nee d t o present evidence that v aries f

rom m em b er to m em

ber. See Tyson Foods, Inc. v. Bouaphakeo , 577 U.S. 442, 453 (2016).

Second, the plaintiffs m

ust show that the cl a s s fits into

one of three categories. See Fed. R. Civ. P. 23(b). To qualify for the third category, Rule 2 3 (b)(3), the district court m ust find that “the que stions of law or fact comm on to class

m em bers predom inate over any questions affecting only individual me mb ers, and that a class action is superior to other available m ethods for fairly and efficiently adjudicating the controversy.” Fe d

. R. Civ. P. 23(b)(3). 5 “The
p r e d o m i n a n c e i n q u i r y a s k s w h e t h e r t h e c o m m o n ,

(3) the claim s or defenses of the represent a t i v e parties are typical of the claim s or defenses of the class; and

(4) the representative parties will fairly and adequately protect the interests of the class.

5 Rule 23(b)(3) provides in pertinent part:

A c l a s s action m ay be m aintained if Rule 2 3(a) is satisfied and if

. . . (3) t

he court finds that the questions

o f l aw or fact com

m on to class m em

bers predom inate

over any questions affecting only individual m em bers, and that a clas s a c t ion is superior t o other available

m ethods for fairl y and efficiently adjudicating the controversy.21

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. B UM B L E B E E F O O D S
aggregation-enabling, issues in the case are m ore prevalent o r im portant than the non-comm o n, aggregation-defeatin g , individual issues.” Tyson Foods
, 57 7 U.S. at 453 (cleaned up). The requirem ents o f Ru l e 23(b)(3) overlap with the requirem ents of Rule 23(a): the p l aintiffs m ust prove that there are “questions of law or fact comm o n to class m em bers” that can b e determ ined in one stroke, see Wal-Mart
, 564 U.S.
at 349, in order to prov e that such comm o n questions predom inate over individualized ones, see Tyso n Foods
, 577 U .S. at 453–54. Therefore, courts m ust consider cases

exam ining both s ubsections in perform ing a R ule 23(b)(3) analysis.

B

Before it can certify a class, a distr i c t co u rt m ust be “satisfied, after a rigorous analysis, that the prerequisites” o f both Rule 23(a) and 23(b)(3) h ave been satisfied. Gen. Tel. Co. of S w. v

. Falcon
, 457 U.S. 147, 161 (1982); Comcast
, 569 U. S. a t 35. “[P]laintiffs wishing to proceed through a class a ctio n m

u st a ctu ally p ro ve—

n ot sim ply plead

—that their proposed class satisfies each requirem en t o f Rule 23, including ( i f applicable) the predom inance requirem ent o f Rule 23(b)(3),” and m

ust carry their burden o f proof “before class certification.” Halliburton Co. v. Erica P. John Fund, Inc. , 573 U.S. 258, 275–76 (2014).

W e have not yet prescribed the plaintiffs’ b u r d en for proving that the prerequisites of Rule 23 are satisfied. In the absence of direction f

rom Congress or the Constitution, it is
up to the court to prescribe the burden of proof. See Herman & MacLean v. Huddleston
, 459 U.S. 375, 389–90 (1983). T o do so, we m

ust consider both the allocation of “ t h e risk o f

error between the litigants” and “the relative im p o rtance22 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

attached to the ultim ate decision.” Id. at 389 (quoting Ad di ngton v. Texas
, 4 21 U.S. 418, 4 23 (1979)). Th e preponderance of the evidence standard allows both parties to “share the risk of error in roughly equal fashion,” id. at 390 (quoting Addington
, 421 U .S. at 42 3 )
, while “[a]ny other standard expresses a p reference fo r o n e side’s interests,” id. Therefore, the preponderance o f the evidence s t a n d a rd is “generally applicable in civil actions.” Id. By contrast, the Court has “required proof b y clear and convincing evidence where particularly im

portant individual interests or rights are at stake,” such as term ination of parental rights or involuntary

comm itm ent proceedings. Id. at 389.

Applying this test here, the balance of interests i n this

case favors prescribing the p reponderance of the evi d ence standard. T he Suprem e Court h as m ade clear that Rule 23 is consistent w ith the Rules Enabling Act and does not “abridge, enl a r g e o r m odify any substantive right.” Shady Grove
, 559 U. S. at 406–07 (citing 28 U.S.C. § 2072(b)). Rule 23 does not “change plaintiffs’ separate entitlem ents to relief nor abridge defendants’ rights” and, instead, alters “only how the claim s are processed.” Id. at 408. T h erefore, th e Sup r e m e Court has concluded that the authorization of class actions is substantively neutral, even though it m ay expose defendants
to the im position of aggregate l iab ility. Id. Because the applicat ion of Rule 23 to certify a class does not alter the defendants’ rights or intere s t s in a substantive way, there is

no basis for applying a heightened standard of proof b eyond the traditional preponderance standard. W e therefore join our sister circuits in concludin g that plaintiffs m u st prove the facts necessary to carry the burden of establishing that the23

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
prerequisites of Ru l e 2 3 are satisfied by a preponderance o f the evidence. 6

In carrying the burden of proving fa c t s necessary for certifying a class under Rule 23(b)(3), plaintiffs m ay u se any adm issible evidence. See Tyson Fo o d s , 5 7 7 U.S. at 454–55 (explaining that adm issib i lity o f ev id en ce at certif icatio n m u st

m eet all the usual requirem ents of adm issibility and citing to Rules 401, 403, and 702 o f t h e Federal Rules of Evidence). Plaintiffs f

requently o ffer expert evidence, including statistical evidence or class-wide averages, to prove that they

m eet the prerequisites o f Rule 23(b)(3). See id. at 455. Where, as h ere, a defendant did not raise a Daubert challenge
to the expert evidence b efore the d istrict court, 7 the defendant forfeits the ability to ar g ue on appeal that the evidence was inadm issib l e , b ut m ay still argue that the evidence is not

c ap able of answering a comm on question on a class- wi d e basis. See Comcast
, 5 6 9 U. S. at 32 n.4; Tyson Foods
, 577 U.S. at 458–59.

In order f or the plaintiffs to carry their burden of proving that a comm on question p r edom inates, they m ust show that the comm on question relates to a central issue in the

6 See I n re Lamictal D irect Purchaser Antitrust Litig.
, 957 F.3d 184, 191 (3d Cir. 2020); In re Nexium Antitrust Litig.
, 777 F.3d 9, 27 ( 1st Cir. 2015); M essner v. Northshore Univ. HealthSystem
, 669 F.3d 802, 8 11 (7th Cir. 2012); A laska Elec. Pension Fund v. Flowserve Corp.
, 572 F .3d 221, 228 (5th Cir. 2009); Teamsters Loc

. 4 4 5 Fr eight Div. Pension Fund v. Bombardier Inc. , 546 F.3d 196, 202 (2d Cir. 2008).

7 In a class proceeding, defendants m ay challenge the reliability of an expert’s evidence under Daubert v. Merrell Dow Pharmaceuticals, I n c. , 509 U.S. 579 ( 1993), and Rule 702 o f the Federal Rules of Evidence. See Tyson Foods , 577 U.S. at 459; see also Comcast , 569 U.S. at 32 n.4.24 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
plaintiffs’ claim

. S

ee Wal-Mart
, 5 64 U.S. at 349–50. Therefore, “[c]onsidering whether ‘questions of law or fact

comm on to class m e mb e r s predom inate’ begins, of course, with the elem ents o f the underlying cause of act i on .” Erica P. John Fund, Inc. v. H

alliburton Co

. , 5 6 3 U.S. 804, 809 (2011) (quoting Fed. R. Civ. P. 23(b)(3)).

The claim s at issue here are violations of section 1 of the Sherm an Antitrust Act, 15 U.S.C. § 1 5, and California’s Cartwright Act, Cal. Bus. & Prof. Code §§ 16700 et seq

. 8 The elem ents o f a cla i m for such antitrust action are (i) the existence o f an antitrust v iolation; (ii) “antitrust injury” o r “im pact” flowing fr om that violation (i.e., the conspiracy); and (iii) m easurable dam ages. See Big Bear Lodgin g As s ’n

v. Snow S

ummit, Inc.
, 1 8 2 F. 3 d 1 096, 1101–02 (9th Cir. 1999); In re Hydrogen Peroxide Antitrust Litig.
, 552 F. 3d 305, 311 (3d Cir. 200 8 )
, as amended (Jan. 16, 2009) (citing 15 U.S.C. § 15). “Antitrust injury” is “injury of the type the antitrust l a ws were intended to prevent and that f lows from that which m akes defend a n t s’ acts unlawful.” Brunswick Corp. v. Pueblo Bowl-O-Mat, Inc.
, 429 U.S. 477, 489 (1977). Dam ages are m easured only after each plaintiff has d em o n strated th at the defendant’s cond u ct cau sed th e p lain

t if f

8 The DPPs claim a violation of t he Sherm an Act, while the CFPs and the EPPs allege violations of California’s antitrust l aw , t h e Car t w r i g h t Act, Cal. Bus. & Prof. Code, § 16700 et seq

. The elem ents o f a Cartwright A ct

c l aim are “(1) t

he form ation and operation o f the conspiracy, ( 2) t h e wrongful act or acts done pursuant thereto, and (3) the d am age resulting from such act or acts.” Marsh v. An e s thesia S ervs. Med. Grp., I

n c. , 132 Cal. Rptr. 3d 660, 670–71 (Cal. Ct. App. 2011) (cleaned up). Because th e a n a lysis of a claim under the Cartwright Act “ m i rrors the analysis under federal [antitrust] l aw,” we do not consider the C artwright A ct claim s separately fromthe federal antitrust claim s. County of Tuolumne v. Sonora Cmty. Hosp. , 236 F.3d 1148, 1160 (9th Cir. 2001).25

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. B UM B L E B E E F O O D S

to suffer an antit ru s t i njury. See In re H ydrogen Peroxide
, 552 F.3d at 311.

Therefore, to p rove there is a comm on question of law o r fact that relates to a central issue in an antitrust class action, plaintiffs m

ust establish that “essential elem ents o f the cause of action,” such a s t h e existence of an antitrust violation o r antitrus t i mpact, are capable of being established through a

comm on body of evidence, applicable to the whole class. Id. (cleaned up). Here, the Tuna Purchasers claim that they can establish the existe n c e o f antitrust im pact through comm on proof.

C

In m aking the determ inations necessary to f ind that the prerequisites of Rule 23(b)(3) are satisfied, the district court

m ust proceed “just as the judge would resolve a dispute about
any other threshold prerequisite for continuing a lawsuit.” In

re Initial Pub. Offerings Sec. Litig.
, 471 F.3d 24, 4 2 (2d Cir. 2006), decision clarified on d enial of reh’g
, 483 F.3d 7 0 (2d Cir. 2007). This m eans that the court m u st m ake a “rigorous

assessm ent of the availabl e e vidence and the m ethod o r

m ethods by which plaintiffs propose to u s e t he [class-wide] evidence to prove” the comm on question in one stroke. In re Hydrogen Peroxide
, 552 F.3d at 312. In addition, the court

m ust find that this comm on question (i.e., the “comm on, aggregation-enabling” issue) predom inates over individual issues. Tyson Foods
, 577 U.S. at 453. The determ ination whether expert evidence is capable of resolving a class-wide question in one stroke m ay include “[w]e i g h ing conflicting expert testim ony” and “[r]esolving e xpert disputes,” In re Hydrogen Peroxide
, 552 F .3d at 323–24, where necessary to

ensure that Rule 23(b)(3)’s requirem ents a r e m et and the26 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

“comm on, aggregation-enabling” issue predo m inates over individual issues, T

yson Foods , 577 U.S. at 453. 9

In determ ining whether the “ c omm on question” prerequisite is m et, a district court is limi t e d to resolving whether the evidence establish e s t hat a comm on question is capable of class-wide resolution, not whether the evidence in fact establishes that plaintiffs would win at trial. While such

an analysi s m ay “entail som e overlap with the m erits o f the plaintiff’s underlying claim ,” Wal-Mart
, 564 U .S. at 351, the

9 Not all expert evidence is capable o f r esolving a class-wide issue in

one stro k e

. Cf. Dissent at 70–71. Courts have frequently f o und t hat

e x p e rt evidence, while otherwise adm issible under Daubert
, was inadequate to satisfy the prerequisites o f Rule 23. For instance, a class did

n o t m e e t the prerequisites of Rule 23 where the expert evidence was inadequate to prove an elem ent o f the claim f or the entire class, see WalMa r t , 5 6 4 U.S. at 354, 3 56, 359 (holding that class m em bers failed t o esta blish existence o f comm on question w ith respect to Title VII claim s because they “ provide[d] no convincing proof of a com panywide discrim inatory pay and prom o tion policy”); where the dam ages evidence

was not consistent with the plaintiffs’ theory of liability, see Comcast
, 5 6 9 U.S. at 35 (holding that at the class certification sta ge, “any m odel supporting a plaintiff’s dam ages case m ust be consistent with its liability case”); where t

he evidence contained unsupported assum ptions, see In re New Motor Vehicles Canadian Exp. An ti tr u s t Litig.
, 522 F.3d 6, 29 ( 1 st Cir. 2008) (criticizing t h e unsupported assum ption that, absent the defendants’ anti-com

petitive conduct, there would have been an i n f lux o f

cars from Canada to United States sufficient t o s ub s t antially decrease national prices); or where the evidence dem onstrated nonsensical results such as f alse positives, i.e., i njury to class m em bers w h o c o uld not logically have been injured by a defendant’s conduct, see In re Rail Freight Fuel S

urcharge Antitrust Litig.-MDL No. 1869 ( Rail Freight I

), 725 F.3d 2 44, 252

– 5 5 (D .C. Cir. 2013) (vacating a certification order where the plaintiffs’ expert evidence predicted that certain plaintiffs had been injured by a price-fixing conspiracy even though t hey operated under fixed-price contracts and were not exposed to overcharges caused by the conspiracy).27

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. B UM B L E B E E F O O D S

“[m ]erits questions m ay be considered [only] to the extent [] that they are relevant to de te rm ining whether the Rule 23 prerequisites for class certification are satisfied,” Amgen Inc.

v. C onn. Ret. Plans & T

r. Funds
, 5 6 8 U.S. 455, 4 6 6 (2013);

see also Ellis v. Costco Wholesale Corp.
, 657 F.3d 9 70, 983 n.8 (9th Cir. 2 011). “Rule 23 g r a nt s courts no license to engage in free-ran ging m erits inquiries at the certification stage.” Amgen , 568 U.S. at 466.

A district court m

ust also resolve disputes about h istorical facts if necessary to determ ine whether the p laintiffs’ evidence is capabl e of resolving a comm on issue central to the plaintiffs ’ claim s. 1 0 For instance, in a case in which a nationwide cla ss of plaintiff em ployees alleged n ationwide discrim ination by their em ployer, we held that a district court had to res o l ve factual disputes at certification regarding whether decisions regarding prom otions were m ade at the local level or b y up pe r m anagem ent. See Ellis
, 657 F.3d at 983–84 & n.7. W e reasoned that if such decisions were m ade only at the local level, plaintiffs “would face an exceedingly difficult challenge in proving that there are questions o f fact and law comm on to the na t ionwide class.” Id. at 983–84. Nevertheless, the district court was no t required to resolve factual disputes regarding ultim ate issues on the m erits, such

as “whether w om en were in f act discrim inat ed against” o r whether the defendant “does in f act have a culture of gender stereotyping and paternalism .” Id. at 983; see also id. at 983 n.8. Resolving such issues w ould “put the c a r t before the horse” by requiring plaintiffs to show at certification that they will prevail on the m erits. Amgen , 568 U.S. at 460.

10 The district court’s findings at the certification stage “do not bind the fact-finder on the m erits.” In re Hydrogen Peroxide
, 552 F.3d at 318.28 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

Therefore, a district court cannot d ecline certification

m erely because it consid ers p lain tif f s’ evidence relating to the

comm on q

uestion to be unpersuasive and unlikely to succeed in carrying the plaintiffs’ burden of proof on that issue. See id. at 459–60. Rather, T

yson Foods established the rule that if “each class m em

b er could h a v e relied on [the plaintiffs’ evidence] to estab l i sh liability if he or she had brought an individual action,” and the evidence “could have sustained a reasonable jury finding” o n the m erits of a comm on question, Tyson F oods
, 577 U.S. at 455, the n a district court m ay conclude that the plaintiffs have carried th e i r bu rden o f satisfying the Rule 23(b)(3) requirem ents as to that comm on question of law or fact. 1 1 In Tyson Foods
, for instance, the Court held that if the class m em bers h a d p u r sued individual lawsuits, each could have re l i e d on the expert evidence
pur porting to show h ow long it took to don and doff protective equipm ent. Tyson Foods
, 5 77 U.S. at 4 56–57. Accordingly, the Court concluded that such expert evidence

was capable of answering a comm on question for the entire class in o ne st r o k e , and could reasonably sustain a jury

11 Senne v. Kansas City R oyals Baseball Corp. referenced Tyson Foods ’ s r ule that a district court m ay deny t he use of adm i ssible expert

e v i d e n c e to m eet t

he requirem ents o f Rule 23(b)(3) only if “‘no reasonable juror’ could find it probative of whether an elem ent of liability

was m et,” and then stated in passing that “ Tyson expressly cautioned t hat this rule should b e read narrowly and n ot assum ed to apply outside of the
wage and hour context.” 934 F.3d 918, 947 & n.27 (9th Cir. 2019) (citing Tyson Foods
, 577 U.S. at 459–60). But Tyson Foods c o n ta i n s n o such lim itation; rather, i t declined to adopt “broad a n d categorical rules governing t

he use of representative and statistical evidence in class actions,” and indicated that district courts should evaluate the sufficiency of plaintiffs’ evidence on a case-by-case basis, depending on t he purpose for which t

he expert evidence is b eing introduced and the underlying

cause of action. 577 U.S. at 459– 6 0. Accordingly, we disapprove t h is dictum in Senne , 934 F.3d at 947 n.27.29

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. B UM B L E B E E F O O D S

verdict in favor of the plaintiffs, even though a jury could still decide t h at t h e evidence was not persuasive. Id

. at 459–60;

see also id

. at 457 (explaining that the question whether the expert’s “study was unrepres e n t ative or inaccurate” was “itself comm on to the claim s m ad e by a l l class m em b ers”). The rule that the evidence need merely be capable o f resolving a com

m on question on a class-wide basis holds true whether the comm on question concerns an elem ent o f plaintiffs’ claim
, see Amgen
, 568 U.S. at 468–69 (m ateriality in a Rule 10b-5 action), o r a fact that m ust be determ ined to

e s t ablish liability, see Tyson Foods
, 577 U.S. at 450 (ti me spent donning and doffing protective equipm ent per week).

Nor can a district court decline to certify a class that will require determ ination of som e individualized questio n s at trial, so long as such questions do n ot predom in a t e over the

comm on questions. S

ee Fed. R. Civ. P. 2 3(b)(3). “Wh en o ne

or m ore o f the central issues in the action are comm on to the class and can b e s a i d to p redom inate, the action m ay be considered proper under R ule 23(b)(3) even though other im portant m atters will have to be tried separately, such a s dam ages or som e affirm ative d efenses pec u l i a r to som e individual class m em

bers.” Tyso n Foods
, 577 U.S. at 453 (internal quotation m arks om itted). Thu s, Halliburton concluded that so long as plaintiffs could show th at t heir evidence is capable of p roving the prerequisites for invoking the presum

ption o f reliance (a key elem ent in a s e c u rities class action) on a class-wide basis, the fa c t t hat the defendants would have the opportunity a t t r ial to rebut that
presum ption as t o s o m e o f the plaintiffs did not raise individualized questions sufficient to defeat predom ina n ce. 573 U.S. at 2 76. “That the defendant m ight attemp t t o p i c k off the occasional class me m ber here o r there through30 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

individualized rebuttal does not cause individual questions to predom inate.” Id.

When individualized questions relate to the injury status of class m em

bers, Rule 23(b)(3) requir e s t hat the court determ ine whether i n d ividualized inquiries about such

m atters would predom inate over commo n qu estions. See Cordoba v. DIRECTV, LLC
, 942 F .3d 1 259, 1277 (11th Cir. 2019). 1 2 In an analogous context, we have held that a district
court is not precluded from certifying a class even if plaintiffs

m ay have to prove individualized dam ag e s a t trial, a conclusion im

plici t l y based on the determ ination that such individualized issues do not predom inate over comm on ones. Vaquero v. Ashley Furniture Indu s

. , In c. , 824 F.3d 1150, 1155 (9th Cir. 2016); see a lso Pulaski & Middleman, LLC v. Google, Inc.
, 802 F.3d 979, 988 (9th Ci r

. 2 015); In re Urethane
, 7 68 F. 3 d 1245, 1255 (10th Cir. 2014) (“The
presence of individualized d am ages issues” does not p reclude

a court from certifying a class because “[c]lass-wide proof is not required for all issues”).

Therefore, we reject the dissent’s argum ent that Rule 23 does not perm it the certification of a c l a ss that potentially includes m ore t h a n a de m inim is num ber of un injured class

m em bers. Dissent a t 77. This position is inconsistent with Rule 2 3 (b)(3), which requires o nly that the dist rict court determ ine after rigorous analysis whether the comm on

12 Because the Suprem e Court has clarified that “ [e]very class

m em ber m u st have A rt i cl e III standing in o rder to recover individual dam ages,” TransUnion LLC v. Ramirez
, 141 S. Ct. 2190, 2 208 (2021), Rule 23 also requires a d istrict court to d eterm ine whether individualized inquiries i nto t

his standing issue would predom inate o v e r c om m o n questions, see Cordoba , 942 F.3d at 1277.31

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
question predom inates over any individual questions, in clu d in g in d iv id

u alized questions about injury o r entitlem ent to dam ages. See Fed. R. Civ. P. 23(b)(3). 1 3

A d i s t r ict court is in the best position to determ in e whether individualized questions, including those regarding class m em

bers’ inj u ry, “will overwhelm comm on ones and render class certification inappropriate under Rule 23(b)(3).” Halliburton
, 573 U.S. at 2 76; see also Ruiz Torres
, 835 F.3d
at 1137 (stating that “the district c o u r t i s well situated to winnow out” a fortui to u sly non-injured subset of class

m em bers). W e “uphold a district court’s determ inat i o n t hat falls w ithin a broad range of perm issible conclusions.” Hung Lam v. City of San Jose
, 8 69 F.3d 1077, 1084 (9th C ir. 2 017)

1 3 T he dissent focuses on policy reasons why d istrict courts sho ul d refra in from certifying classes that m ay include m ore than a de m inim is

num ber of uninjured class m em bers. Dissent at 64, 75, 7 7–78. But we are bound to apply Rule 23(b)(3) as written, regardless of policy preferences. And contrary to the d issent’s assertion, our conclusi o n t h a t courts m u st

ap p l y Rule 23(b)(3) on a case-by-case basis, rather than rely on a per se rule t hat a class cannot b e certified if it includes m ore than a de m inim is

num ber of uninjured class m em bers, i s consistent with the approach taken by our sister circuits. Dissent at 78. N either of the two cases cited by the dissent, In re Rail Freight Fuel Surcharge Antitrust Litig.-MDL No. 1869 ( Rail Freight II

), 934 F.3d 619 (D.C. Cir. 2 019) and In re A sacol Antitrust Litig.
, 907 F.3d 4 2 (1st Cir. 2 018), adopted a p er se rule. Rather, based o n the particular facts of the cases before them
, ou r s i s t e r circuits held t hat Rule 23(b)(3)’s predom inance requirem ent is not satisfied when the need
to i dentify uninjured class m em bers “will p re d o m inate and render an adjudication unm anageable.” In re Asacol Antitrust Li t i g

. , 907 F.3d at 53–54; see also Rail Freight II
, 9 34 F.3d at 625 (holding t h a t a district
court did not abuse i ts discretion in denying class certification where the plaintiffs “proposed no further w ay

— sh o r t o f f u l l

- b l o w n , i n d i v i d

u a l trials”
to determ ine the comm on question of whether class m em b e rs were injured).32 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
(quoting Kode v. Carlson
, 596 F.3 d 6 0 8
, 612 (9th Cir. 2010)). 1 4

III

W e now turn to t h e Tu n a Suppliers’ argum ents and consider them in light of this legal fr a m ework. W e begin with the DPP class, which is the focus of the Tuna Suppliers’

14 Nevertheless, a court m ust consider whether the possible presence of uninjured class m em

bers m eans t

hat th e c l a s s definition is fatally overbroad. W hen “a clas s i s d e fined so broadly as to include a great

num ber o f m em

bers who for som e reason could not have been harm ed b y the d e fe n dant’s allegedly unlawful conduct, the class is defined too broadly t o perm i t certification.” Messner
, 669 F.3d at 824; see also Mazza

v. Am. H onda Motor Co.
, 666 F .3d 581, 596 (9th Cir. 2012) (holding t hat the class definition i n a f alse advertising action was fatally overbroad where m any m em

bers learned that the advertising was m isleading before purchase or had never been e x p o s e d to the allegedly m isleading advertisem ents); In re Asacol
, 9 0 7 F.3d at 55–58 (holding t h at the class did not m eet Rule 23(b)(3) r equirem ents because the plaintiffs’ evidence showed that thousands of plaintiffs who were loyal to brand-nam e drugs would not h ave purchased the generic drugs that were the s ub j e c t o f the price-fixing conspiracy). In such a ca s e , th e court m ay redefine the overbroad class to include o nly those m em bers who can rely on the sam e body of comm o n evid e n ce to establish the comm on issue. See, e.g. , Mazza
, 666 F.3d at 596 (holding that false advertising “clas s m u s t be defined in such a way as to i n c lude only m em bers w ho were exposed to advertising that i s alleged to be m aterially m isleading”). A court m ay not, however, create a “fail s afe ” class that is defined to include only those individuals who were injured by t he allegedly unlawful conduct. See Ruiz To r r es , 8 3 5 F.3d at 1138 n.7 (internal quotation m arks om itted). “Such

a class definition is im

p roper because a class m em ber either wins o r, by virtue of losing, is defined out of the class and is therefore not b o und b y the jud gm ent.” Messner
, 6 69 F.3d at 825. But, ultim ately, the problem of a potentially “over-inclusive” class “can and often should be solved b y refining the class definition rather than by flatly denying class certification on that basis.” I

d.33

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

argum ents. In order to prevail on thei r a n ti t rust claim
, the DPP class m

ust prove that t h e Tuna Suppliers engaged in a conspiracy (an antitrust violation), which resulted in antitrust im pact in the form of higher price s pa i d by each m em b er o f the class, which in turn led to m e a su r able d am ages. The
ques t ion whether each m em b er of the DPP class suffered antitrust im

pact “i s c e n t r a l to the validity of each one of the [DPP] claim s. ” Wal-Mart
, 564 U.S. at 350. The central questions on appeal are wh e th e r the expert evidence presented by the DPPs is capable of resolving th is i s su e “in

one stroke,” id.
, a nd whether this comm on question predom inates o ver any individualized inquiry. W e conclude that the district court did not abuse its discretion in certifying the class.

A

The centerpiece o f the DPPs’ claim that each m em ber o f the class suffered a n t itrust im pact is econom ist D r. R

ussell Mangum ’s expert testim o n y a n d report. According to his testim o ny an d rep o rt, D r. Man g um rev iew ed a co m p rehensive
range of available inform ation to develop an understanding o f the nature of the m arket at issue an d the details of the Tuna Suppliers’ price-fixing conspiracy. That inform ation included court fi l i ngs, the Tuna Suppliers’ guilty pleas, discovery m aterials such as the Tuna Suppliers’ b u s i n ess records concerning t h ei r sales of packaged tuna, deposition testim ony, publicly available inform ation regarding the tuna industry, and data regarding supply and dem and factors that affect the m anufa c tu re, sale and consum ption o f packaged
tuna such as raw m aterial prices and d etails about custom er preferences.34 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

After exam ining th e e c onom ic structure of the tuna

m arket an d t

h e av ailab le r eco rd ev idence concerning the Tuna Suppliers’ behavior, Dr

. M angum determ ined that the packaged tuna m arket was conducive to price-fixing, given the Tuna Suppliers’ dom inance in the m arket, the attendant barriers to entry for com

petit o rs, the Tuna S uppliers’ use o f price lists for their p r o du cts, and other characteristics of the packaged tuna i ndustry. According to Dr. Mangum
, these findings supported a baseline econom ic theory that the Tuna Supplier s ’ collusive behavior would affect the DPPs on a class-wide basis. Dr. Man g um th e n used a num ber o f different econom etric tools t o evaluate whether quantitative evidence supported this theory. 1 5

Dr. Mangum first perfo r me d a pricing correlation test, which dem onstrated that the prices of the Tuna Supplie rs’ products m o ved up or down together regardless of product o r custome r type, and thus supported the proposition that the Tuna Suppliers’ collusion had a comm on, supra-competitive im pact on their p rices. Based on this evidence, Dr. Mangum concluded that the Tuna Suppliers’ collusion would result in higher prices that w ould affect direct purchasers o n a c lasswi d e basis, which was consistent w ith his original the o ry

. This finding i s also consistent with “the p revailing [econom ic] view [that] price-fixing affects all m arket participants, creating an inference of class-wide im pact even when prices are individually n egotiated.” In re Urethane
, 768 F.3d at 1254.

15 Econom etrics is “the application of statistical m ethods to econom ic data

. . . to draw inferences about econom ic relationships from observed data on m arket o utcom es [i.e., price], even when thos e outcom e are the result of com

plex interactions am ong num erous econom i c f o rces.” Econometrics at 1.35

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

To f urther explore whether the DPPs were s ubject to an overcharge caused by the price-fixing conspiracy (rather than b y o ther v ariables that could affect prices) o n a class-wi d e basis, Dr. Mangum constructed a st atistical m odel using a

m ultiple regression analysis. Regression analyses are used to determ ine “the relationship betw een an unk n o wn [ d ependent]

va riable [such as p rice] and one o r m ore independent variable s [e.g., transaction characteristics, and supply and de m a n d factors] that are thought to im pact the dependent variable.” Id. at 1260 (quotation m arks o mi tted) (citing Michael J. Saks, et al., Reference Manual o n S cientific Evidence 179, 181 (2d ed. 2000)). If a regression m odel uses “appropriate indep e ndent [or explanatory] variables,” it can test and isola t e t h e extent to which the actual prices p aid by plaintiffs are higher because of a d efe n dant’s collusive behavior. Id. Assum ing D r. Mangum ’s regression m odel m et this standard, it could provide f urther evidence that the DPPs

were imp a cted by the Tuna Suppliers’ collusion on a classwide basis.

In sim ple t e r m s , Dr. Mangum first aggregated (or “pooled”) the actual tuna sale transaction data fo r the Tuna Suppliers’ sales to the DPPs during both t h e a l leged conspiracy p eriod and during benchm ark periods before and after the conspiracy. Dr. Mangum then identified a nu mb e r of variables (referred to as independent or explanatory variables) that cou l d affect the price of tuna, including produ ct characteristics, input costs, custom er type, and variables related to consum er preference and dem and, such as disposable income
, s e asonal effects, and g eography. The

m odel then isolated (or “controlled for”) the e ffe ct of these explanatory variables on the pric e s p a id by D PPs, which allowed the m o del to isolate the effect that the conspiracy by itself h ad on the prices paid by DPPs. When all the tuna sale36 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

t ransactions were aggregated, and the explanatory variable s (other than the price-fix ing conspiracy) were controlled for, the m odel showed that the D PPs p aid 10.28 percent m ore for
tuna during the conspiracy period t h a n t h ey did during the benchm ark periods. Dr. Mangum labeled this 10.28 p ercent

as the “overcharge,” m eaning the comm on am ount paid by the D PPs resulting fro m t h e c ollusive b ehavior alone. This result was statistically significant, m eaning that there was a less than five percent chance that the higher prices during the price-fixing conspirac y was a product of chance. Thus, by isolating the com

m on overcharge am ount , Dr. Mangum ’s regression m odel was further confirm ation of his theory that the Tuna Suppliers’ collusion had a class-wide effect. 1 6

Dr. Mangum perform ed s e veral tests (which he referred
t o as “robustness checks”) to confirm that his regress i o n

m odel wa s an appropriate tool to b e used by the entire DPP class to s h ow comm on im pact. These tests were used to confirm the r eliability of the m odel, and, according to Dr. M a ng um , the test results supported his ultim ate

c o nclusion that the m odel could be u sed to show class-wide

16 T he dissent argues that D r. Mangum ’s opinion is not persuasive because large retailers have barga ining p ower and can extract price discounts, prom otional credits, and rebat e s

. Dissent at 72–73. As the dissent concedes, Dissent at 73 & n. 5, Dr. Mangum took these issues into
account (to the extent that the Tuna Suppliers provided relevant dat a). After doing so, Dr. Mangum ran the regression m odel using both gross and net prices and determ ined that his regression m odel c ontinued to produce a statistically significant overcharge. D r. Mangum therefore reasoned that discounts and p rom otions did not affect his pooled m odel o r his conclusion of class-wide im pact. Although the dissent argues that (in the dissent’s v iew) Dr. Mangum did not consider price di s c o u nts, prom otional credits, and rebates “adequately,” Dissent at 73 & n

. 5, the persuasiveness o f Dr. Mangum ’s analysi s i s n o t at issue at this phase o f the proceeding.37

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
injury. First, Dr. Mangum changed the m odel to evaluate the overcharge specific to each individual defendant. T h e results showed that p rices wer e still elevated above com petitive levels during the collusion p e r i o d. Second, Dr. Mangum changed the m odel to evaluate the o v ercharge specific to certain p roducts with differen t c haracteristics, such as fish type and package type. These tests showed that each type o f product tested was im

pacted to a sim ilar degree. Th i r d
, Dr. Mangum changed the m odel to evaluate the o vercharge based on custom er types. 1 7 This test showed that there were large, statistically significant overcharges for every custom er type. These robustness checks confirm ed Dr. Mangum ’s theory that the DPPs p aid an o vercharge during the conspiracy per i o d. Finally, Dr. Mangum used the output o f the pooled regression m odel to p redict the but-for prices (i.e., what the price of tuna d

uring the conspiracy period wo u l d have been without the overcharge caused by the conspiracy),

a n d com p ared these predicted but-for prices to the actual pric e s paid by the DPP class. T his com parison showed that 94.5 percent o f t he purchasers had at least one purchase above the predicted but-for price
, which again provided further evidence that the conspiracy had a comm on im p act on all or nearly all the m em

bers of the DPP class. 1 8 Dr. Mangum

17 D i re ct purchasers were g rouped into categories called custom er types, which included Retail, Club, Special Market, Food Service, Mass Merchandise, Discount, and e-Com m erce.

18 According to Dr. Mangum
, the purpose o f this robustness test was to dem onstrate t

hat his regres si o n m od el was sound. Contrary to the dissent’s asserti o n , D issent at 66, Dr. Mangum did not “suggest” t hat 5.5 percent of the class were uninjured. Rather, Dr. Mangumconcluded that each class m em

ber was i njured by supra-com petitive prices, and used

a d ifferent m ethodology for calculating d am ages for each m em ber of the class. S ee infra at n.19. T he Tuna Suppliers do not develop the argum ent38 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

therefore concluded that h is aggregated regression m odel provided econom etric evidence that the conspiracy resulted in higher p rices paid by all o r nearly all DPPs. According to Dr. Mangum
, the results w ere s t rong evidence of comm on, class-wide antitrust im pact. 1 9

In sum , Dr. Mangum ’s findings about the tuna m arket and th e T un a S u

p p liers’ c o llu siv e b eh av ior, his pricing correlatio n test, his regression m odel, and his robu st n e ss checks all confirm ed his th e o ry that the conspiracy resulted in substantial price im

pacts, and that the im

p act was comm on to the DPPs during the collusion period.

B

The Tuna Suppliers attacked Dr. Mangum ’s expert report

on m u lti ple fronts, but prim arily relied on their rebuttal expert, econom ist Dr. John Johnson, who m ade m u ltiple criticism s of Dr

. Mangum ’s m ethodology. The essence o f

that t he results of this robustness t est preclude certification of the class as currently defined. Therefore, we do not address this issue h e re

. See Unite d States v. Sineneng-Smith
, 140 S. Ct. 1575, 1578 (2020); see also Tyson Foods , 577 U.S. at 460 (declining to reach a sim i lar issue).

19 A l t h o u g h the regression m odel prim arily served as evidence o f clas s -w i d e antitrust im

pact, Dr. Mangum used the overcharge derived from the r egression m odel to estim ate class-wide dam ages. This estim ate

was developed by m

ultiplying the overcharge estim ate of 10.28 percent b y the appropriate sales v olum e for the defend a n t s , adjusted by several pertinent factors. Dr. Mangum used the sam e m ethod to estim ate dam ages for each of the class representatives identified in the com plaint. The Tuna Suppliers do not challenge Dr. Mangum ’s dam ages m ethodology. Thus,
t h e d i s s e nt’s contention that the court has created a “sweeping rule t hat gives a free pass to the intractable pro b lem o f highly individualized dam ages analyses” m isses the m ark. Dissent at 74.39

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

Dr. Johnso n ’ s c r itique was that it was not statistically appropriate to use a pooled regression m odel for transactions in the tuna m arket, g iven the m u ltiple individualized differences am ong class m em b e r s, such as disparities in negotiating tactics and bargaining power. Dr. Mangum ’s use of pooled data, Dr. Johnson alleged, m asked these individual differences am ong class m e mbers. Thus, Dr. Johnson claim ed, Dr. Mangum ’s conclusion that the conspiracy h ad a class-wide im

p act based o n a uniform overcharge d id not reflect the real world.

Dr. Johnson supported this allegation on several grounds. First, Dr. Johnson claim ed that a statistical tool called a Chow
test 2 0 shows that the data relating to tuna transactions should
not be pooled due to individ u a l d ifferences in each purchaser’s transactions. S econd, Dr. Johnson critici zed Dr. Mangum ’s calculation that 94.5 percent of DPPs wh os e transactional data were included in the m odel had at least o ne purchase at a price abov e the predicted but-for price. Accor di n g to Dr. Johnson, this calculation was m isleading because it was prem ised on what D r. Johnson characterized

as the faulty assum

ption that all direct purchas ers paid the

sam e 10.28 percent overcharge throughout the proposed class period. Instead, Dr. Johnson perform ed his own test o f Dr

. M a n gum ’s m odel. As part of this test, Dr. Johnson changed the m o d el to evaluate overcharge based on each individual custom er. A ccording to Dr. Johnson, the test showed that o f the 604 d irect purchasers who bought f rom the Tuna S uppliers during the proposed class p e riod, the m odel did not estim ate a positive and statistically significant

20 A Chow t est is a statistical test designed to “determ ine w h e t h er i t is appropriate t o pool potential s ub g ro ups when estim ating the average effect of the alleged conspiracy.” Econometrics at 358.40 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
overcharge (attributable to the conspira cy) for 169 direct purchasers (or 28 percent). Therefore
, Dr

. Johnson argued that the plaintiffs could not rely on the m odel to dem onstrate class-wide impact of the conspiracy. 2 1

Dr. Johnson m ade several additional critiques in arguing that Dr. Mangum ’s m odel was not capable of dem onstrating class-wide im

pact. First, Dr

. Johnson argued that Dr

. M a ngum ’s m odel showed false p ositives. According to Dr. Jo h n so n , an application of Dr. Mangum ’s regression

m odel showed that several DPP class m em bers h a d p aid an overcharge when they purchased tun a p r o ducts from nondefendants, i.e., tuna suppliers who had not participated in the conspira c y. Second, Dr. Johnson attacked the reliability o f Dr. Mangum ’s m odel because Dr. Mangum ’s m odel selected tim e periods that d id not precisely m atch the class periods in the DPPs’ com

plaint. Finally, Dr. Johnson criticized Dr

. Mangum ’s use of a cost index (a calculated m easure o f
costs for all the Tuna Suppliers) as one of the explanatory

var i ab les in his m odel, rather than using actual accounting
cost data. According to Dr. Johnson, the use of a cost index inappropriat e l y assum ed that the T una Suppliers’ costs responded in a like way to supply and dem and factors.

In rebuttal, Dr. Mangum rejected D r. Johnson’s prem ise that a pooled, aggregated m odel was inappropriate to use in

21 D r. Johnson’s test attem pted to show that Dr. Mangum ’s m odel was flawed because 169 direct purchasers could not rely on the m odel to show antitrust i m

pact due to the fact (as Dr. Mangum subsequently explained) that som e purchasers h a d n o o r too few transactions during t he precollusion benchm ark period to g e n e rate statistically significant results. Contrary to the d issent’s claim
, Dissent at 66, Dr. Johnson d id n o t s how that 28 percent of the class poten t i ally suffered no injury. See infra Section IV.B.41

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

this case. D r. Mangum explained that his technique was a

we ll-known and well-accepted m ethod for exam ining antitrust im

pact in m arkets with individualize d d ifferences

am ong purchasers. According to Dr. Mangum
, b oth of the bases f or Dr. Johnson’s challeng e s to the u se of a pooled regression m odel failed. Firs t , Dr

. Mangum claim ed that a Chow test should not b e used in the m anner em ployed by Dr. Johnson in his repor t. According to Dr. Mangum
, Dr. Johnson’s Chow test was “designed to fail,” m eaning that in this context, the test results w ould always s h ow that the data relating t o tuna transactions should not be pooled. Second, Dr. Mangum a s serted that the record contained insufficient transaction data for Dr. Johnson ’s test of the regression m odel to y ield m eaningful re s u l t s

. For exam ple, Dr. Mangum acknowled g e d that the m odel, as changed by Dr. Johnso n to consider purchasers on an individual basis, could not estim ate a positive and statistically significant

ove r charge for 169 direct purchasers. But according to Dr. Mangum
, no regression m odel could yield a statistically significant estim ate for m any of those 169 direct purchasers

on such an individual purchaser-by-purchaser basis, because 61 of those purchasers did not m ake any purchases during the benchm ark periods, and m any of the other purchasers had not undertaken a sufficient num ber of transactions during either the benchm ark periods or collusion period to yield statistically significant results. A nd logically, D r. M angum asserted, given the evidence that the defendants were able to inflate prices generally through the conspiracy, that the tuna

m arket was susceptible to collusion, and that the m odel showed a robust, statistically significant im pact of the pricefixing sch e me on the tuna m arket, even the DPP class

m em bers for wh o m Dr. Johnson’s test did not yield a positive, statistically significant overcharge should be able to rely o n the pooled regression m o d el as evidence of im pact.42 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

Therefore, according to Dr. Mangum
, Dr. Johnson erred in concluding that the regres s i o n m odel had no relevance for that 28 percent of class m em bers.

Dr. Ma n gum also rebutted Dr. Johnson’s additional critiques. W ith respect to D r. Johnson’ s claim that the

re g ression m o del yielded false positives, Dr. Mangum explained that overcharges im posed by non-defendant tuna suppliers (who were not part of the conspiracy) w ere not false positives b ut were caused by the “um brella effect.” This term refers to an econom ic observation that when m any suppliers
engage in a conspiracy to raise prices, non-conspirators m ay raise their prices to supra-competitive levels because o f the conspirator’s dom inant m arket po we r. See ABA Section o f Ant itrust Law, Proving A ntitrust Damages: Legal & Economic Issues 226 (2d ed. 2 010). Dr. Mangum also argued that D r. Johnson’s claim of false positives was based o n an

erroneous analysis of the tuna m arke t

. According to Dr. Mangum
, D r. Johnson incorrectly claim ed that two of the individual DPPs (Sysco and U .S. Foods) purchased tuna from non-defendant suppliers because both of those class m em bers actually p urchased tuna that was produce d by the Tuna Suppliers and m erely sold t h r o u gh a m iddlem an. Dr. Mangum defended his selection o f tim e periods re l a ti n g to the m odel, claim ing he narrowed the class period based on his analysis of the evidence in the case. F inally, Dr. Mangum rejected Dr. Johnson ’ s c ritique of h is use of cost indexes. Dr. Mangum asserted t hat costs indexes were statistically superior to using individual cost acco u n t i n g data. He noted that one of the robustnes s t e sts he perform ed on the data showed tha t using defendant-specific cost structures confirm ed the results of the pooled m odel. A nd h e a s s erted
t h a t it was preferable to use his cost index f or determ ini n g

com petitive m arket price s based on m arket supply and43

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

d emand conditions, rather than relying on cost data derive d fr o m t he Tuna Suppliers’ individual approaches to cost accounting.

C

In considering whether the DPPs’ ev i d e n ce was capable

o f e stablishing antitrust im pact for the class as a whole, t h e district court reviewed Dr. Mangum ’s exp e r t testim o ny and report, the rebuttal testim ony and report by Dr. Johnson, and Dr. Mangum ’s reply, a

n d th en addressed the p arties’ disputes. In doing so, the district court did n ot m ake a n y l eg al o r factual error.

F irst, the district court considered D r. Jo hn so n ’s argum ent that Dr. Mangum ’s pooled regression m odel m asked d if f e ren ces b etween p urchasers, and th at wh en th e o v erch arg e is determ ined for individual DPP class m em bers the m odel did not show a positive, statis tically significant im pact for

som e 28 percent of the class. After reviewing each of the experts’ analyses, the d istrict court credited Dr. Mangu m’ s rebuttal o f Dr. Johnson’s critique. Even if the mo d e l ( when

m odified by Dr. Johnson to evaluate individual purchas e rs) did not yield a positive, statistically significant o v erch arg e f o r

som e purchasers who had no or too few transactions during the p re-collus i on benchm ark period, the district court concluded that those purchasers could still rely on the pooled regression m odel as evidence of the conspira cy ’ s im pact on sim ilarly situated class m em bers. The court further noted that other evidence in the record
, including the g u ilty pleas and

m arket characteristics, showed that class m em bers suffered a

comm on im

p act.44 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

The district court also considered Dr. Johnson’s argum ent that the Chow test showed that Dr. Mangum ’s m odel cannot be applied to all defendants. The court acknowledged that failure of a statistical test u sed to determ ine whether a regression is appropriate should be taken seriously, and could lead a court to reject the m odel at the class certification stage

as not capable of p roviding c l a s s

- wide proof. But it also noted that m o st regressions m odels will fail one or m ore tests i f enough are run, even if the m odel itself is statistical l y sound. Because there w as a rational basis for Dr. Mangum ’s

use o f the pooled regression m odel to dem onstrate class-wide im pact, the court concluded t h e f ailure of the Chow test did not require the court to reject the m odel.

The district court rejected Dr. Johnson’s additional
argum ents. W ith respect to Dr. Johnson’s claim that the false
p os i tives in Dr. Mangum ’s m odel rendered the m od el unreliable, the court credited Dr. Mangum ’s explanation that the false positives could be explained by the um brella effect and that Dr. Johnson h ad erroneously concluded that som e tuna wa s supplied by non-defendants when in fact the tuna

was supplied b y defendants. The district court also addressed
t h e d ispute over Dr. Mangum ’s selection of the tim e pe r i o d for the class, and concluded that Dr. Mangum ’s narrowing o f the tim e fram e bolstered the reliability of the m o del. Finally, the di s t rict court rejected Dr. Johnson’s critique o f Dr. Mangum ’s use of a cost in d e x, rather than actual accounting cost data. T h e court credited Dr

. M angum ’s explanation as to why the use o f such an index provided m ore reliable results than actual cost accounting data, and concluded that his u se of a cost index did not underm ine the reliability of his m ethodology or m odel.45

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. B UM B L E B E E F O O D S

After resolving each dispute betwe e n the experts, the district court acknowledged that the defendants’ critique o f Dr. Mangum ’s m odel could be persuasi v e t o a jury at trial. But the district court recognized that a t t hi s stage of the proceedings, its task was to determ in e wh eth er Dr. Mangum ’s evidence was capable of showing cl a ss

- wide im pact, not to reach a conclusion on the m erits of the DPPs’ claim s. After weighing the evidence put fo r t h b y the DPPs, including the

r egression m odel, the correlation tests, the record eviden c e and the g uilty pleas and adm issions entered in this case, the district court concluded there was sufficient evidence to show

comm on q

uestions predom inated as to comm on im pac t

. Therefore, it ruled that this prerequisite to Rule 23(b)(3) was

m et.

W e conclude that the district court di d n ot abuse its discretion in reaching this conclusion

. T he court conducted

a rigorous anal y sis o f the expert evidence presented by the parties. The district court d id not err legally o r f actually in concluding that D r. Mangum ’s pooled regression m odel,

a l o ng with other evidence, is capable of answering t h e question whether there was antitrust im pact due to the collu s i o n on a class-wide basis, thus satisfying this prerequisite of Rule 23(b)(3).

IV

W e now turn to the Tuna Supp l i e r s ’ claim s that the district court abused its discretion in determ ining that the evidence presented by the D PPs proved: (1) that the elem ent of antitrust im

pact is capable of being established class-wide46 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

t hrough comm on proof, and (2) that this comm on questi o n predom inates over individual questions. 2 2

A

The Tuna Suppliers’ m ain argum ent is that the district
court abused its discretion in determ ining that Dr. Mangum ’s

m odel is capab l e o f p roving comm on im pact for all class

m em bers. According to t h e Tuna Suppliers, Dr. Mangum ’s evidence is not a permi s s ible m ethod o f proving class-wide liability because th e r e gression m odel uses “averaging

assum ptions,” m eaning that the m odel assum es that all DPPs

were ove r c h a rged by the sam e uniform p ercentage (10.28 percent). These averaging assum ptions, according to the Tuna Suppliers, “paper over” i n dividualized d ifferences

am ong class me mbers. Because the tuna m arket is characte rized by individualized negotiations and different bargaining power am ong the purchasers, the Tuna Suppliers claim it is f

undam entally im

possible to show comm on proof of injury. To support this argum ent, the Tuna Suppliers note that the DPPs who pursued their antitrust claim s individually did not rely on a pooled regression m odel but used actual cost d ata and claim ed an individualized o vercharge rate. Gi v e n the n ature of the tuna m arket, the Tun a Suppliers conclude,

22 T h e Tuna Suppliers do n o t ch a l lenge the district court’s gateke e p i n g f

unction under Daubert
, to ensure t hat Dr. Mangum ’s evidence was n ot “statistically i nadequate o r base d o n im plausible

assum ptions.” Tyson Foods
, 577 U.S. at 459. And c o n trary to the dissent’s argum ent, Dissent at 6 9
, the district court did not m erely determ ine that D r. Mangum ’s ev i d e nce w as adm issible under D aubert

. R ather, it subjected the evidence to a rigorous exam ination with full consideration of Dr. Johnson’s critique. Therefore, the dissent’s assertion that the d istrict court comm itted the sam e error as the district court in Ellis is m isplaced. Dissent at 68–69.47

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. B UM B L E B E E F O O D S

Dr. Mangum ’s m odel ca nn ot m eet the prerequisites o f Rule 23(b)(3).

To the extent that the Tuna Sup p l i ers argue that pooled
reg ressio n m o d els involve im prop er “av erag in g a ssu

m p t i o n s ” and therefore are inherently unreliable when used to analyze

com plex m arkets, we disagree. In antitrust cases, regression

m odels have b een widely accepted as a generally reli able

econom etric technique t o c o n trol for the effects o f the differences am ong class m em bers and isolat e t h e im

pact o f the alleged antitrust violations on th e prices paid b y class

m em bers. 2 3 See
, e.g. , Econometrics at 1. Furthe r , Tys on Foods rejected any categorical e x c l u sion of representative 2 4

or statistical evidence. 577 U.S. at 45 9

– 6 0. Therefore, any categorical a rgum ent that a pooled regression m odel cannot control f or variables relating to the individualized d ifferences

am ong class m em

b ers m ust be rejected.

23 See, e.g. , Kleen Prod. LLC v. Int’l Paper Co.
, 831 F.3d 91 9, 9 2 9 (7th Cir. 2016); In r e Urethane
, 768 F.3d at 1263; Cordes & Co. Fin. Servs. v. A .G. Edwards & Sons, I nc. , 502 F.3d 9 1, 97, 107 (2d Cir. 2007); Hemmings v. Tidyman’s Inc.
, 285 F.3d 1174, 1188–89 (9th Cir. 2002); I n re Linerboard Antitrust Litig. , 305 F.3d 145, 153 (3d Cir. 2002).

24 Although the Tuna Suppliers refer to Dr. Mangum ’s regression

m odel as “representative evidence,” that term i s im precise. As explained in Tyson Foods
, representative evidence generally refers to a sam ple t hat
represen t s the class as a whole. See 577 U.S. at 454

– 55. Thus, Tyson Fo ods concluded that each individual in a class could rely o n exem plars of persons donning and doffing protective equipm ent to prove the am ount of tim e each spen t d o nning and doffing; t his sam ple was claim ed to be representative of all m em bers o f the class. See id. By contrast, a regression m odel analyzes available data t o determ ine t he degree to which a known variable, such as collusion, affected an unknown variable, such as price, while elim inating the effect of other variables.48 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

To the extent the Tuna Suppliers and the dissent raise the

m ore focused argum ent that, in this case, the m odel’s output (estim ating that the Tuna Suppliers’ conspiracy resulted in a 10.28 p ercent overcharge for the e n t i r e class) cannot plausibly serve as comm on evidence fo r a ll class m em bers give n t he individualized differences am ong those class

m em bers, w e again disagree. 2 5 It is not im plausible to conclude that a conspiracy c ould have a class-wide im pact, “even when the m ar k e t involves d iversity in p roducts,

m arketing, and prices,” especially “where, as he re, there is evidence that the conspiracy artificially inflated the baseline for price negotiations.” In re Urethane
, 768 F.3d at 1254–55. As the Tenth Circuit explained, a district court could reasonably con c lude “that price-fixing would have affected the entire m arket, raising the baseline prices for all buyers.” Id. at 1255. In other words, it is both logical and plausible that the conspiracy could have raised the baseline p rices fo r all m em bers of the class b y roughly ten p ercent. T he district court did not abuse its discretion in so concluding.

The dissent argues that Dr. Man gum ’s expert opinion “flies against comm on sense and em pirical evidence,” because large retailers like W alm art likely would have used their bargaining power to negotiate lower prices, and thus

m ay not have paid h igher prices b e c a u se of the Tuna Suppliers’ collusion. Dissent at 72. But the district court is
not free to prefer i t s own views about the econom ics of the

25 To the extent the Tuna Suppliers challenged the m odel’s inputs, the district court considered and rejected D r. Johnson’s critique t h at som e o f the m odel’s inputs ( i.e., the u s e o f a cost index and Dr. Mangum ’s selection of tim e periods) rendered the m odel incapable of dem o nstrating

c l a s s -w ide im

pact. Cf. In re Lamictal
, 957 F.3d at 194 (holding that the district court abused its discretion in c e rt i fying class because it failed to scrutinize each expert’s data).49

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

tuna m arket over the statistical evidenc e subm itted by the plaintiffs
, a nd here the regression m odel controlled for the variables identified b y t h e d issent. Indeed, Dr. Mangum provided an individualized o v ercharge estim ate for W alm art when he changed the m odel to evaluate the overcharge based

on c u s tom er types. This test showed that W alm art paid
st a t i s t i c a l l y si g n i fi c a n t o vercharges because of the conspiracy. Provided that th e evidence is adm issible and, after ri g o r o u s review, determ ined to be capable o f establishing antitrust im

pact on a class-wide basis, it is for the jury, not the court, to decide the per s u a s i v eness o f Dr

. Mangum ’s evidence in light of “comm on sense and

em pirical evidence.”

The Tuna Suppliers rely on I n re New Motor Vehicles Canadian Ex

p ort Antitrust Litigation
, 5 22 F.3d 6 (1st Cir. 2 0 08), for the proposition that a m arket involvi n g individualized negotiations is inherently incom patible with

comm on im

pact. This reliance is m isplaced. 2 6 In New Motor Veh i cl e s , plaintiffs raised a “novel and com plex” theory o f how consum e rs were injured b y defendants’ alleged horizonta l conspiracy to discourage im ports of lower-cost

cars from Canada into the United States. Id. at 27. Plaintiffs’ theory proceeded in two steps: (1) “bu t for the defendants’ illegal stifling of com

petition,” m anufacturers would have set lower prices to co mp e t e with C anadian im ports; and (2) b ecause the m anufacturers did not do so, consum ers paid higher retail prices. Id. The First Circuit rejected this theory

26 A s a threshold m atter, the First Circuit held in New Motor Vehicles that the district court lacked federal jurisdiction over the plaintiffs’ claim s, but went on to provide its thoughts on certification of the class in the event the district court exercised its discretion to exert supplem ental jurisdiction over the state dam ages claim s. 522 F.3d at 17.50 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

because p laintiffs failed to dem onstrate they had an approach for proving either step. For the first step, plaintiffs had not shown how they would establish that b u t fo r the h orizontal conspiracy, enough lower-priced Canadian cars would flood into the Am erican m arket so as to c a u s e m anufacturers to decrease their prices. Id. A s for the second step, the plaintiffs h ad not proved their dam ages m odel was capable o f

s ho wing “which consum ers were im pacted by the alleged antitrust violation and which were not.” Id. at 2 8

. In this regard, the p laintiffs relied on an inference that “any upward
p ressu re o n national pricing would necessarily raise the p rices actually paid by individual c o n s u m ers.” Id. at 2 9. But the First Circuit rejected this inference because “[t]oo m any factors play into an individual negotiation to allow an

a s s u m p t i o n

— a t l e a s t w i t h o u t f u r t h e r t h e o r e t i c a l development

—that any p rice increase or d ecrease will always have the sam e m agnitu d e o f effect on the final price paid.” Id. at 29 (em

phasis a d d e d ). The court contrasted the plaint iffs ’ unsupported inference with cases allowing “a
presum ption of class-wide im

pact in price-fixing cases when ‘the price structure in the industry is such that nationwide the conspiratorially affected p rices at the who le sale level fluctuated within a range which, though different in different regions, w as higher in all regions than the range which would have existed in all regions unde r com p etitive conditions.’” I d. (quoting In re Linerboard Antitrust Litig.
, 305 F.3 d 1 4 5
, 151 (3d Cir. 2 002)). Despit e r e jecting the plaintiffs’ theory
at an early stage of t h e c ase, the court did not rule out certification of a class but instead concluded that “m ore work

rem ained to b e done in the building of p l a i ntiffs’ d am ages

m odel and the filling out of all steps of plaintiffs’ the o ry o f im pact.” Id.51

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

As this explanation of the case m akes clea r , New Motor Vehicles ’ a n alysis is not applicable h ere. First, the DPPs’
p rice-fixing theory is not “novel” or “com plex.” Id. at 2 7

. Rather than adopting a theory requiring m ultiple speculative steps, the DPPs have a sim ple one-step theory: the Tuna Suppliers conspired to raise tun a prices, resulting in higher prices for all buyers. S econd, while the plaintiffs in New Motor Vehicles h ad not provided a thor ough explanation o r de ve l oped a m odel showing h ow they w ould establish their theory
, id. at 29, the DPPs have already offered welldeveloped expert t e s t im o ny and regression m odeling supporting comm on im

pact. The other cases relied on by the Tuna Suppliers are equ ally inapposite. See, e.g. , B lades v. Monsanto Co.
, 400 F .3d 562, 572 (8th Cir. 2005) (affirm ing denial of class certification because evidence of a conspiracy
to raise prices, without m o re, could not dem onstrate im pact

across highly localized and h ighly individualized m arkets for hundreds of seed varieties, and the plaintiffs had not offered

a comm on m ethod of showing injury); Robinson v. Tex. Auto. Dealers Ass’n
, 387 F.3d 416, 423 (5th Cir. 2004) (reversing

c lass certification where the plaintiffs lacked a plausi b le theory of how the challenged conduct had consistently affected purchase prices).

The Tuna Suppliers also argue that because the individual plaint iffs pursuing their own antitrust claim s showed overcharges both above and below the overcharge indicated by Dr. Mangum ’s m o d el, a uniform 1 0.28 percent o vercharge is im p lausible. W e als o r eject this argum ent, because it im properly conflates the qu e s tion whether evidence is capable of proving an issue on a class

- wide basis with the question whether the evidence is p e r s u a s ive. A lack o f persuasiveness is n ot fatal at certification. See Amgen
, 568 U .S. at 459–60. For purposes of d et e r mi n ing whether52 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

each m em ber of the DPP class can rely on the m odel to prove antitrus t impact, it is irrelevant whether actual sales data shows a specific class me mb e rwas o vercharged by m o re o r less than 10.28 percent. Rather, the q uestion is whether each

me mber of the class can rely on Dr. Mangum ’s m odel t o show antitrust im

pact of any a mo unt. T he district court did
not abuse its discreti o n i n finding that each m em ber could. While individualized d ifferences am ong the overcharges im posed on each p urchaser m ay require a court to determ ine damages on an individualized basis, see supra Section III.C, such a task would no t underm ine the regression m odel’s ability to p rovide evidence o f comm on impact

. Accordingly,

we reject the Tu n a Suppliers’ argum ent that the regression

m odel co u l d not sustain liability in individual proceedings. Rather, “each class m em

ber could h ave relied on [the m odel]
to establish li ab i l ity if he or she had brought an individual action.” See T

yson Foods
, 577 U.S. at 455. W e therefor e conclude that the district court did not err legally or factually in concluding t hat Dr. Mangum ’s pooled regression m odel does not f

ail on any of the grounds ra i s e d b y the Tuna Suppliers. 2 7

B

The Tuna Suppliers and the d issent next contend that the district court erred by failing to resolve a dispute between the parties as to whether 28 percent of the class did not suffe r

27 The T una Suppliers do not “specific a l l y a n d distinctly” raise the
argum ent that the district court abused i ts discretion in resolving ch a l l e n g e s to the inputs to the m odel which w ere raised below, such as D r. M a ngum ’s choice of b enchm ark p eriod and use of cost indexes, so that argum ent is deem ed forfeited on appeal. United States v. Kama
, 394 F.3d 1236, 1238 (9th Cir. 2005).53

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. B UM B L E B E E F O O D S

antitrust im

pact. Instead of resolving the dispute between the parties’ experts, the Tuna Suppliers claim
, t h e d i strict court im properly shifted the cri tical inquiry to the jury. In other words, the T una Suppliers argue that to s a t i sfy Rule 23(b)(3)’s predom inance requirem ent, plaintiffs m ust prove that all or nearly all class m em bers were in fact injured by the alleged conspiracy, i.e., suffered antitrust im pact. 2 8

In raising this ar g u me n t, the Tuna Suppliers focus on Dr. Johnson’s critique of Dr. Mangum ’s m odel, which stated that when he t ested Dr. Mangum ’s m odel by changing it to evaluate the overcharge specific to each individual m em ber of the DPP class, the test showed that 28 percent of the DPPs could not rely on t h e mo del to show an o vercharge attributable to the co n s p i r acy. A ccording to the Tuna Suppliers, this evidence indicated that 28 percent of the DPP class did not suffer antitrust im pact. And in district court, the Tuna Suppl ie r s argued that “28% of a class—nearly onethird—far exceeds the d

e minimis num

ber o f uninjured class

m em bers that som e courts have perm itted in certifying a

c l a s s .” Therefore, the Tuna Suppliers argue that the cl a s s should not h ave been certified. Further, the Tu n a Suppliers
argue that the existence of a large num ber of uninjured class

m em bers raises a question as to whether the class has Article III standing. The Tuna Suppliers contend that bec ause the class cannot be certified (and there are Article III issues) if Dr. Johnson’s analysis is correct, the district court abused its discretion in failing to resolve the dispute regarding whether

28 Because the Tuna Suppliers’ prim ary argum ent on appeal is that the DPPs failed to prove class-wide antitrust i m pact, we understand the Tuna Suppliers’ reference to injury as referring to antitrust im pact, an elem ent of the class antitrust claim s, not that the class m em bers would n ot be able to prove that they suffered m onetary dam ages.54 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

Dr. Johnson’s conclusions about Dr. Mangum ’s m odel were correct.

W e d isagree. First, the Tun a Supp l iers and the dissent mi s characterize the im port of Dr. Johnson’s critique

. Dr. Johnson did not m ake a f actual finding that 28 percent o f the DPP class or 1 6 9 class m em b ers were uninjured. Instead, Dr. Johnson’s test was aim ed at undermi n ing confidence in Dr. Mangum ’s pooled regre s s i o n m odel, because class

m em bers with no or lim ited transaction s during the benchm ark period could n ot rely on the m odel t o show that they suffered overcharges. At m ost, this critique supports the

m ore attenuated argum ent th at Dr. Mangum ’s m odel is unreliable, or would be unpersua s i v e to a jury. But the district cou r t considered and resolved this m ethodological dispute between the experts in favor o f Dr. Mangum by crediting his rebutta l th at even class m em bers with lim ited transactions du r in g t he class period can rely on the pooled regression m odel as evidence o f im pact on sim ilarly situated class m em

bers. In other words, the d istrict court determ ined that Dr. Mangum ’s pooled regression m odel was capable o f showing that the DPP class m em bers suffered antitru st i m

pact

on a class-wide basis, notwithstanding D r. Jo hn so n ’s critique. This was all that was necessary at the certification stage. The DPP class did not have to “first establish that it will w in the fray” in order to g a in certification under Rule 2 3(b)(3). Amgen
, 5 68 U.S. at 460. Nor is this a ca s e s u c h a s Ellis
, in which the court had to resolve a dispute regarding an issue o f historical fact in order to determ ine wh e ther the challenged discrim inatory conduct could a ffe ct a class as a whole. See 6 57 F.3d at 983. There is no f actual dispute that the Tu n a Suppliers engaged in a price-fixing schem e affecting the entire packaged tuna industry nation-wide.55

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

The district court’s conclusion that the Tuna Supplie rs could present D r. Johnson’s critique at trial did not im properly shift the burden of determ ining whether the Rule 23(b)(3) p rerequisites were m et to the jury. 2 9 See Amgen
, 568 U.S. at 459–60, 4 66. The di s t r ict court fulfilled its obligation to resolve the di s p u te s raised by the parties in

or d e r to satisfy itself that the evidence proves the prerequisites fo r Ru le 23(b)(3), which is that the evidence

was capable of showing t hat the DPPs suffered antitrust im pact on a class-wide basis. “Reasonable m inds m ay differ

as to whether the [ overcharge Dr. Mangum ] c a l culated is probative” as to all purchasers in the class, but t h a t i s a question of persua s i v e n es s for the jury once the evidence is sufficient to satisfy R

ule 23. See T

yson Foods
, 57 7 U. S. at 459.

Ne ither Dr. Mangum ’s pooled regression m o del nor Dr. Johnson’s critique required individualized inquiries into the cl a s s m em

bers’ injuries. If the jury found that Dr. Mangum ’s m odel was reliable, then the DPPs would have succeeded in showing antitrust im p act o n a class-wide basis,

an elem ent of their antitrust claim

. On the o ther hand, if the jury were persuaded by Dr. Johnson’s critique, the jury could conclude that the DPPs had f ailed to prove antitrust im

pact on

29 The Tuna Suppliers do n ot “specifically and distinctly” develop the
argum ent that the district court failed to resolve the parties’ dispute as to whether the evidence generated false positives. Kama
, 394 F.3d at 1238. In any event, as explained above, Dr. Mangum r ebutted these critiques b y reference t o the u m

bre lla effect, and by claim ing that Dr. Johnson’s analysis was i tself flawed because Dr. Johnson t hought D PP c lass

m em b e rs had purchased non-defendant tuna, when they actually purchased tuna supplied b y defendants. The district court did not abuse its discretion in resolving this issue by crediting Dr. Mangum ’ s rebuttal.56 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

a class-wide basis. 3 0 In neither case would the litigation raise individu al i z ed questions regarding which m em bers o f the DPP class had suffe r e d an injury. Although such issues would have to be addressed at the dam age s stage, the dissent’s argum ent that the district court here erred by failing
to determ ine whether questions of indivi du a lized d am ages predom inate, Dissent at 74, m isses the m ark. As noted above, the Tuna Suppliers have n ot argued tha t the com plexity o f da m ages calculations would defeat predom inance h ere, and

as previously explained, there is no per se rule that a district
court is precluded from certifying a c lass if plaintiffs m ay have to prove individualized dam ages at trial. 3 1

W e need not consider the Tuna Suppliers’ argum ent that the possible p r esence of a large num ber of uninjured class

m em bers raises an Article III issue, b e c a use the Tuna Purchasers have dem onstrated that all class m em ber s h a v e

30 A lthough Dr. Johnson argued that Dr. Mangum ’s pooled regression

m odel was unreliable and so could not sustain a jury fi nding of antitrust injury to the entire DPP class, the evidence adduced at tria l m ay neverth eless sustain a jury f inding o f antitrust injury to all or part of the class.

31 I n any event, Dr. Mangum ’s proposal for calculating dam ages is a straightforward process of applying the class-wide overcharge to the Tuna Purchasers’ net sales records. See supra n.19. Th a t p ro posal d oes not give rise to a concern about individualized m ini-trials t o determ ine each class m em

ber’s dam age award. “ That the d efendant m ight attem pt to pick off the occasional class m em ber here or there through indiv i du alized rebuttal d oes not cause individual questions to predom inate.” Halliburton
, 573 U.S. at 276.57

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. B UM B L E B E E F O O D S
standing here. 3 2 A plaintiff is required to establish the elem ents necessary to prov e standing “with the m anner and degree of evidence required at the successive s t a g e s of the litigation.” Lujan v. Defs. of Wildlife
, 5 0 4 U.S. 555, 561 (1992). H ere, the district cour t c on c luded that the DPPs’ evidence was capable o f establ is hi n g antitrust im pact on a class-wide basis. Because a n ti t rust im pact—i.e., that the Tuna Suppliers’ collusion had a comm on, supra-competitive im pact on a class-wide basis—is sufficient to show an injuryin-fact t r a c eable to the defendants and redressable by a favorable ruling, the Tuna Purchasers have adequately dem onstrated Article III sta n d i ng at the class certification stage for all class m em

bers, whether or not that w as required. See TransUnion , 141 S.Ct. at 2208 n.4.

32 The Sup re m e Court expressly held o pen the question “whether
every class m em

ber m ust dem onstrate standing before a court certifies a class.” T ransUnion
, 141 S.Ct. a t 2 2 0 8 n.4 ( em phasis om itted). Outside the class action context, the Suprem e Court has held t h a t e a c h plaintiff

m ust dem onstrate Article I II standing in order to seek add i tional m oney dam ages and, therefore, a litigant m ust dem onstrate Article III standing in order to interven e a s a m a t t e r of right. Town of Chester v. Laroe Ests., Inc.
, 137 S.Ct. 164 5
, 1651 (2017). But the Suprem e Court has long recognized t

hat in cases seeking injunctive or declaratory relief, only o ne plaintiff need dem o n strate standing to satisfy Article III. See, e.g. , Baggett v. Bullitt
, 377 U.S. 360, 366 n.5 (1964); Rumsfeld v. F

. for Acad. & Institutional Rts., Inc.
, 5 47 U.S. 4 7, 52 n.2 (2006); Horne v. Flor e s , 557 U.S. 433, 446–47 (2009). W e have likewise applied this rule where

a class sought i njunctive or equitable relief. See Bates v. Unit e d Parcel Serv., Inc.
, 511 F.3d 974, 985 (9th Cir. 2007) (en b a n c ). W e therefore overrule the stat e m e n t i n Mazza that “no class m ay be certified t hat

co ntains m em

bers lacking Article III standing,” 666 F.3d at 594, which does not apply when a court is certifying a class seekin g injunctive o r other equitable relief. W e do not overrule Mazza as to any other holding which rem ain good law.58 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
Accordingly, we affirm the district court’s certification o f the DPP class.

V

W e n ext turn to the Tuna Suppliers’ argum ents that the district court abused its discretion in determ ining that the evidence presented by the CFPs a n d EPPs was capable o f proving the elem ent of antitrust im pact under California’s Cartwright Act, thus satisfying the prereq uisites of Rule 23(b)(3).

A

The CFP subclass inclu d e s individuals and comm ercial entities who purchased b ulk sized packaged tuna (packa ges of 40 ounces o r m ore) from six com panies (direct purchasers) which had purchased the tuna from the Tuna Suppliers. The CFPs’ theory of antitrust im pact proceeds in two steps. F irst, the CFPs claim

that the Tuna Suppliers’ conspiracy resulted i n the d irect p urchasers paying an overcharge. Second, t h e CFPs claim that the o vercharge was passed on from the direct purchasers to the CFPs.

The CFPs supported this theory with the expert testim ony and report of econom ist Dr. Michae l Wi l liam s, who

em ployed a m ethodology sub stantially sim ilar to that

em ployed by Dr. Mangum

. Dr. W illiam s first condu c ted a regression analysis to d et erm ine the overcharge the CFPs’ suppliers (i.e., the six direct purchasers) incurred because o f the Tuna Suppliers’ collusion. L ike Dr. Mangum ’s analysis, Dr. W illiam s’s regression analysis controlled for the effect o f other variables that affected price in order to isolate the effect of the Tuna Suppliers’ collusion. Dr. W illiam s concluded59

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

that COSI overcharged the CFPs’ direct purchasers by 16.6 percent, StarKist by 18.2 percent, and Bum ble Bee by 15.3 percent.

Next, Dr. W illiam s perform ed a separate regression analysis to d eterm ine if those overcharges passed through to the CFPs, and determ ined tha t the direct purchasers passed through 92 to 113 percent of their overcharge to the CFPs. Dr

. W illiam s then perform ed two tests to verify that his estim ates applied class-wide, both of whic h c on firm ed his theory.

To rebut Dr. W illiam s’s analys i s , the Tuna Suppliers relied o n a critique by econom ist Dr. Linda Haider. Dr. Haider asserted that D r. W illiam s erroneously assum ed that all CFPs paid a comm on overcharge and t h a t th e sam e

ove r c harge was passed through to the individual CFPs. Dr. Haider also contended that som e o f t h e CFP class

m em b e r s, such as food preparers and distributors, were not im pa c te d because they could have passed through their overcharges to other purchasers downstream

. Finally, Dr. Haider claim ed that Dr. W illiam s’s m odel was unreliable because it f

ailed to account for non-defendant tuna purchased by the CFPs’ direct purchasers.

The di s t r i ct court reviewed Dr. W illiam s’s report and testim ony as well as Dr. Haider’s critiques, and after resolving the parties’ disputes, concluded that Dr. W illiam s’s

m ethodology was valid and capable of resolving the antitrust im pact issue in a single s troke, even though the Tuna Suppliers could raise the sam e critiques at tr i a l to persuade the jury.60 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

On appeal, the Tuna Suppliers argue that the district court abused i ts d iscretion in concluding that Dr. W illiam s’s

m ethodology satisfi e d Rule 23(b)(3)’s requirem ent o f

comm on proof of antitrust im pa c t, because Dr. W illiam s erred in assum ing that all direct purchasers w ere overcharged by the sam e perce ntage and that each class m em ber was subject to the sam e p ass-through rate. W e dis a g r ee

. A s explained in Section IV, supra , a district court does not abuse i t s discretion in concluding that a regression m odel such a s the on e u s e d b y Dr. W illiam s m ay be capable o f showing class-wide antitrust i mp act, provided that the district court considers f

actors that m ay undercut the m o del’s reliability (such as unsupported assum ptions, erroneous inpu ts, o r nonsensical outputs such as false positives) and resolves disputes raised by the parties. T he d istrict court did so in this
case, and therefore d id n ot abuse its discretion in concluding that Dr. W illiam s’s m ethodology was reliable and capable o f showing class-wide impact.

W e also reject the Tuna Supp li e rs’ argum ent based on Dr. Haider’s contention that som e CFP class m em bers m ay have passed on their overcharges to downstream purchasers. Dr. H aider cl a i me d that the CFPs’ ability to prove comm on im pact was p roblem atic because the im p act o f o v ercharges on class m em

bers who passed on their overcharges would be different from the im

pact o n m em

bers who did not p ass on such overcharges. The district court d i d not abuse its discretion in rejecting this argum ent on the g ro u n d t h a t the Tuna Suppl i e r s had n ot shown that determ ining whether o r not those class m em

bers had passed overcharges down the distribution chain would overwhelm the comm o n issues and require a n i n dividualized analysis. Therefore, the district
court could reasonably conclude that the comm on question o f61

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

antitrust im

pact predom inated over individualized questions concerning a passed-on overcharge.

B

The EPP subclass c o n t ains individual consum ers who purchased the Tuna Suppliers’ products f or personal

consum ption. Thus, like the CFPs, the EPPs are indi r ect purchasers whose theory of antitrust im pact depends on two
separa t e o vercharges: first, an overcharge by the Tuna Suppliers to the direct p urchasers (i.e., retail stores), and then

an overcharge passed on to the EPPs. To carry their burden of showing they could establish class-wide overc h arges through comm on pro of, the EPPs offered the testim ony o f

econom ist Dr. David Sunding, who em p loyed a m ethodology substantially sim ilar to that em ployed by Dr

. Mangum and Dr. W illiam s.

Like Drs. Mangum and W illiam s, Dr. Sunding first conducte d a r e gression analysis to isolate the im pact of the

c o l lusion on the direct purchasers, which he concluded was

an 8 .1 percent overcharge from C OSI, 4.5 percent from StarKist, and 9.4 percent f rom Bu mb l e Bee. He then determ ined th a t the overcharges passed through to the E P P class m em

bers ranged from 65.3 to 135 per c e n t with an estim ated pass-th r ough rate of 100 percent for the entire class. Dr. Sunding provided qualitative, quan t i ta t ive and anecdotal evidence to support his assum pti o n of a pass through rate for the entire class, including an exam ination o f retail scanner data and the Tuna Suppliers’ internal records.

Dr. Haider critiqued Dr. Sunding’s m ethodology and find i n g s o n m any of the sam e g rounds as she criticized Dr. W illiam s’s m odel and conclusions. Sh e also m ade the62 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

additional criticism s that Dr. Sunding’s m ethodology produced absurd results because it sho we d prices that m ade

no econom ic sense, and that his m odel ignored, and therefore failed to control for, im

portant factors like loss-leader a n d focal p oint pricing. The district court analyzed the evidence and the experts’ disputes, a n d concluded that Dr. Sunding’s report and testim o n y were capable of showing antitrust im pact com m on to the class, for the sam e reasons explained in the court’s analysis o f Dr

. Mangum ’s and D r. W illiam s’s

m odels. Th e district court determ ined that Dr. H aider’s additional critiques were based either on a mi s r eading o f Dr. Sunding’s report, or her own m iscalculations.

On appea l
, t h e Tuna S uppliers argue only that Dr. Sunding’s m odel an d t e stim ony w as not capable o f proving comm on im

pact f or all class m em

bers because o f its

use of “averaging assum

ptions.” T his argum ent f

ails for the

reasons explained above. See supra Section IV.A. Thus, the district court pro p erly considered and rejected Dr. H aider’s
argum ents, and determ ined that Dr. Sunding’s m ethodology

was capable of proving antitrust im pact on a class-wide basis. That is enough to satisfy Rule 23(b)(3).

VI

In a com plex m arket such as the one at issue here, where different purchasers with d ifferent bargaining power purchased a range of products at different prices from different suppliers, comm entators have raised reasonable questions whether statistical m odels are capable of resolving the issue of antit ru st im

pact with comm on proof. See, e.g. , Michelle M. Burtis & D arwin V. Neher, Correlation and Regression Analysis in Ant it rust Class Certification
, 77 Antitrust L.J. 495, 518 (2011). But such statistical m odels63

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. B UM B L E B E E F O O D S

and other evidence have b een accepted as probative in a range of litigation contexts, and the Suprem e Court has m ade clear that the perm issibility of statistical evidence “turns not on the fo r m a proceeding takes—be it a class o r individ u al action—but on the d egree to which the evidence is reliable in proving or disproving the el e me n ts of the relevant cause o f action.” Tyson Foods
, 577 U. S. a t 4 55. Here the district
court did not abuse its discretion in rigorously analyzing such statistical evidence, determ ining that it was not flawed in a

m anner that would m ake it incapable of p roviding class-wide proof, see supra Section III.C, conclu d i n g that the evidence

was sufficient to sustain a jury verdict on the que stion o f antitrust im

pact for the entire class, and prese r v ing the defendants’ ability to challenge the p e r s u a siveness of such evidence at trial. W e therefore affirm the district court ’s decision to certify the Tuna Purchasers’ three subclas s e s under Rule 23(b)(3). Ne v ertheless, the Tuna Suppliers will have th e opportunity to convince a jury that not all class

m em bers were overcharged due to their collusion.

AFFIRMED.

LEE, Circuit Judge, with whom KLEINFELD, Circuit Judge, joins, dissenting:

Over the past two decad es, p laintiffs have notched over $103 b illion in settlem ents from securities class act i ons alone. 1 If we include other types of class actions—wage and

1 See Securities Class A ction Settlem ents—2019 R e view and A n al y si s, H arvard Law School F o rum on Co r p o r at e G o v er

n an ce, av ai l ab l e at https://corp g o v

. l a w

. h a rv a rd

. e du / 2 0 2 0/03/11/securities-class-action-64 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

hour, consum er lawsuits, antitrus t d isputes, and m any others—that settlem ent am ount alm ost certainly swells up by
tens of billions of dollars m ore. These settlem ent sum s a re

s ta g gering b ecause class action cases rarely g o to trial. I f trials these days are rare, clas s a c t i o n trials are alm ost extinct. 2 And it is no wo nd er why class actions settle so often: If a court certifies a class, the potential liability at trial becom es enorm ous, m aybe even catastrophic, forcing

com panies to settle even if they have m eritorious defenses.

That is why the Suprem e Court has urged lower courts to “rigorous[ly]” scrutinize whether plaintiffs have m et class certification requirem ents. See Wal-Mart Stores

, I n c

. v. Dukes
, 564 U.S. 33 8
, 3 5 1 (2011). The m ajority opinion, however, allows the district cour t t o c e rtify a class, even though potentially about one out of th r e e class m em bers suffered no injury. But if defendants’ econom etrician expert is correct that a l most a third o f the class m em bers m ay not have suffered injury, plaintiffs have not shown the predom inance of comm on issues under Rule 23(b).

The district court a cknowledged the dueling experts’ differing opinions on this crucial que st i o n but held that it would leave that issue for another day—at trial—beca u s e it involves a m erits issue that a jury should decide. See In re Packaged Seafood Prods. A ntitrust Litig.
, 332 F.R.D. 308,

settlem ents-2019-review-and-analysis/ (last visited Oct. 21, 2021).

2 See, e.g. , Securities Clas s A c t i on Filings, 2020 Year in Review, Cornerstone Research, at 18, available at https://www.cornerstone.com/ P u b l i c a t i o n s / R e p o r t s / S e c u r i t i e s

- C l a s s

- A c t i o n

- F i l i n g s

- 2 0 2 0

- Y e a r

- i n

Review (last visited Oct. 21, 2 021) ( noting only 11 securities class action

c a s e s tried to verdict in the past quarter century and only one t r i ed sinc e 2014).65

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

325–28 (S.D. Cal. 2019). But as a practical m atter, that d ay will likely never com e to p a s s because class action cases alm ost always settle once a court certifies a class. A district
court thus m

ust serve as a gatekeeper to r e s o lve key issues im plicating Rule 23 requirem ents—including wh ether too

m any putative class m em

bers suffered no injury—at the class certification st a g e

. S

ee Med. & Chiropractic Clinic, Inc. v. Oppenheim
, 98 1 F.3d 9 83, 992 (11th Cir. 2020) (“Rule 23

m akes clear that the district court in whi c h a c l a ss action is filed operates as a gatekeeper”).

Punting this key question until later am o unts to handing victory to plaintiffs because this case will likely settle without the court ever deciding that issue. The refusal to address this key dispute now is akin to the NFL dec l i ning to review a critical and close call fumb l e du r ing the waning m inutes o f the gam e unless and until the g am e reaches overtim e (which, of course, will likely n ever o cc u r if it does not decide the disputed call). Such a practi c e i s neither fair n o r true to the rule.

I thus respectfully dissent.

* * * * *

The U .S. Departm ent of Justice’s investigation revealed that the three largest dom estic producers of p a c k aged tuna colluded t o t ry to inflate the prices of their products. This class action lawsuit soon followed the crim inal indictm ent. Am ong the plaintiffs include the direct purchasers of the tuna products, ranging f

rom m ultibillion d ollar cha i n retailers to

sm all m om -and-pop stores. Not surprisingly, som e plaintiffs (such as W alm art) wield substan t ial n egotiating leverage: They can d em and lower prices or extract additional66 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

prom otional credits or rebates that defr a y the offered price. In contrast, an owner of a bodega likely cannot dem and even

an audience with the tuna producers, let alone ask for lowe r prices or m ore prom otional credits.

Despite the varying negotiating power am ong the plaintiffs, their expert, Dr. Russell Mangum III, concluded that the tuna producers o vercharged the direct purchasers by

an average of 1 0.28%. He also suggested that about 5.5% o f the class m ay not have suffered an injury b e c a use of this price-fixing. In contrast, the d efend a n ts ’ expert, Dr. John Johnson, offered an analysis showing that potential ly about 28% of the class m em

bers suffered no injury.

Fac e d w ith this gaping difference between the two experts’ conclusions, the d istrict court acknowledged that Dr. Johnson’s “criticism s are serious.” In re Pa ckaged Seafood
, 332 F. R. D. a t 328. But it held that this question should b e l eft for trial because Dr. Mangum ’s m ethod was reliable under D aubert and “ capable o f showing” class-wide im pact. Id. The m ajority agrees with the district court, ruling that a class can be certified—even if potentiall y o n e out o f three m em

bers suffered no injury—because Plaintiffs’ expert offered a m ethod “capable” of m easuring class-wide impact and the district court can winnow out tho s e u n injured

m em bers later at trial. B ut the m ajority opinion conflicts with Rule 23’s text, comm on sense , an d precedent from other circuits.67

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. B UM B L E B E E F O O D S

I. The district court did not “rigorously” sc rut iniz e the dueling experts’ opinions about uni njured class members.

While around 10,000 cla ss action lawsuits are filed annually 3

, class actions are “an exception to the usual rule that litigation is conducted by and on behalf of the individual

n am ed parties only.” Comcast Corp. v. Behrend
, 569 U. S. 27, 3 3 (2013) (quoting Ca li f ano v. Y amasaki
, 442 U.S. 682, 7 0 0–01 (1979)). Rule 2 3 thus establishes stringent requirem ents for certifying a class.

Am ong the Rule 23 requirem ents, the plaintiff m u st show that “qu estions of law or fact comm on to class m em bers predom inate over any questions affecti n g only individual

m em bers.” F ed. R. C iv. 23(b)(3). The word “ c omm o n”

me ans “belonging to or shared

. . . by all m em be r s o f a gro up ,” while “predom inate” m eans “to hold advantage in

num b e rs or quantity.” 4 Rule 2 3(b)(3) thus requires that questions of law or fact be sh a r e d b y a ll or substantially all

m em bers of the class.

The Suprem e Court has also rem inded u s that Rule 23 does not esta b l i s h a “m ere pleading standard.” Wal-Mart
, 564 U.S. at 350. R ather, plaintiffs m ust prove by a preponderance of the evidence that they have m et the Rule 23 requirem ents. See i d

. ; M a j

. Op. at 22–23. Rule 23 im poses

3 Class Actions 2021
, Lexology, Jo nathan D. Polkes and David J. Lender, eds., at 91 (2021).

4 “Comm on” and “predom inance,” M erriam-Webster Dictionary, available at www.merriam-webster.com/dictionary (last checked on Oct. 21, 2021).68 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

a requirem ent on the trial court, too. A trial court can certify

a class only aft er engaging in a “rigorous analysis” and determ ining that the p laintiff has satisfied Ru le 23. WalMart
, 5 64 U .S. at 351. And in conducting that “rigorous analysis,” trial courts “[f]requently” m ust assess “the m erits of the plaintiff’s underlyin g claim ” because the issues are often intertwined. Id.

Rule 23’s “rigorous analysis” is different from “reliable”

or “relevant.” Ellis v. Costco Wholesale Corp.
, 657 F.3d 970, 982–84 (9th Cir. 2011). A trial court m ust do m ore than just consider o ne side’s expert opinion as “reliable” and then kick the can d o wn the road until trial. Rather, it m ust dig into the weeds and d ecide the battle of dueling experts if their dispute im plicates Rule 23 requirem ents.

Here, the two experts’ con t e n t ions centered on Rule 23(b)(3)’s predom inance requirem ent—whether it has been m et if the defendants’ expert concludes that potentially

a sig n ificant num

ber of putative class m em bers were uni n jured. Plaintiffs’ expert argued that only about one out of twenty class m em

bers likely did n ot suffer an injury, while d efendants’ expert m aintained it was potentially m ore t h a n

one out of four. Th e d i s t rict court held that the plaintiffs’ expert’s opinion passed m uster under D aubert but adm itted that the defendants’ expert offered “serious” criticism, t o o. The district court adm irably analyzed this difficult issue but ultim ately did not resolve it, ruling that a jury should decide it at trial.

Despite the detailed analysis of the district court, I believe it abused its discretion in com m itting the sam e error that we cautioned against in Costco. There, the two dueling experts offered contrasting opinions o n whether Costco’s alleged69

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. B UM B L E B E E F O O D S

discrim ina tion was regional or n ationwide, which touched
upon Rule 23(a)’s comm onality requirem ent ( i.e.
, whether all
t h e p u t a t i v e c l a s s m e m b e r s n a t i o n w i d e s u f f e r e d discrim ination). The trial court h eld the plaintiffs’ expert was reliable under D aubert
, and declined to d ecide which experts’ opinion should prevail at the class certification stage. It then certified a clas s a n d ruled that this “battle of the experts” issue could be decided at trial because Costco’s criticism s o f
t h e ex p ert report “attack the weight of the evidence and n o t its adm issibility.” Id. at 982 (quoting district court opinion).

But because that dispute im p licated Rule 2 3(a)’s

comm onality requirem ent, we reversed the distric t court’s certification o rder and directed it to address it at the class certification stage. As we put it, the trial court “confused” the Daubert standard’s “reliable” requirem ent with the “rigorous analysis” standard for Rule 23. Id. at 982 (“Inst ead o f j u d gi n g the persuasiveness of the evidence presented, the district court see me d t o end its analysis of the plaintiffs' evide n c e after determ ining such evidence was m erely adm issi b l e

. ” ). R ather than “exam ining the m erits [of the dispute between experts] to decide this issue,” the trial court “m erely concluded that, because both P l aintif fs’ and Costco’s evidence was adm issible
, a finding o f comm o nality was appropriate.” Id. at 984. That was error.

And that is exactly what happened here. The district
court found plaintiffs’ expert to be reliable un d er Da ubert
, but it also conceded that the defendants’ e x p ert offered a “serious” critique of p laintiffs’ ex p e r t opinion. The district
court ultim ately held that resolving this “battle of the experts”

was a m erits issue. But the disp u te over the num ber o f uninjured class m em

bers ov erlaps with Rule 2 3(b)(3)’s predom inance requi r e m ent as well as Rule 23(a)’s lower70 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

t hreshold comm onality requirem ent. Sim ply put, a plaintiff
cannot p rove that comm on i s s u e s predom inate if o ne out o f three putative class m em

bers suffered no harm

. Cf. Mazza v. Am. Honda Motor C

o., Inc.
, 666 F.3d 581, 5 96 (9th Cir. 2012) (“[T]he relevant class m u st be d efined in such a way as to include only m embers who were [harm ed by being]
exp o s e d to advertising that is alleged to be m aterially

m isleading.”). If a large num ber of class m em

bers “in fact suffered no injury,” ide n t i fy ing those class m em bers “will predom inate.” In re As ac o l Antitrust Litig.
, 9 07 F.3d 42, 53–54 (1st Cir. 2018). Thus, the district c o u r t had to “exam in[e] the m erits” of this dispute between the e xp erts, and not “m erely conclude[] t hat” both expert reports are reliable and adm issible. Costco , 657 F.3d at 984.

The m ajority holds t h at Dr. Mangum ’s estim ate of a 1 0

. 2 % “av erag e” p rice in f

lation m eets R

u le 2 3 ’s req

u irem ents because it shows a m e th o d “ capable” of showing comm on antitrust im

pact. The m ajority appears to distinguish between (i ) cases in which the class m em bers “ logically ” could not have been h arm ed (because, for ex a m ple, they were never exposed to the m isleading advertisem ent) or there is insufficient evidence to support comm onality, and (ii) cases like this one in which an expert holds t h a t ma ny class

m em bers in reality m ay not have suffered any harm
, even if they theoreticall y c ould h ave. Maj. O p. 26, n.9. In the form er scenario, th e m ajority says that a class cannot be certified because logically there cannot be comm onality under R ule 23; in the latter case, the m ajority appears to argue that it is a m erits issue b ecause a jury will need to assess the persuasiveness of the expert’s opinion.

I believe that creates a false distinction. N othing in our decision in Costco or th e Suprem e Court’s opinion in71

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. B UM B L E B E E F O O D S

Wal-mart creates such a difference. If the evidence presented im plicates Rule 23—as it does here—then the district court must decide whether the plaintiffs have “prove[n] that the r e

are in f a c t

. . . comm on questions of law or fact,” even if it

m eans assessing the persuasivene ss of the expert o pinions. Wal-mart
, 5 64 U.S. at 350–51 (em phasis i n o riginal). In Costco
, we chastised the district court for not “judging the persuasiveness o f th e evidence presented” and “end[ing] its analysis of t he plaintiffs' evidence after d eterm ining such evidence was m erely adm issible.” 6 57 F.3d at 982. If we had to refrain from

deciding the persuasiveness of an expert opinion used to show comm o n ality, a p laintiff could prevail

on class certifica t i o n by m erely offering a well-written and plausible expert opinion. See West v. Pr udential Sec., Inc.
, 282 F.3d 935, 938 (7th Cir. 2002) (failure to resolve dueling

e xperts “am o unts to a delegation of judicial power to t h e plaintiffs, who can obtain class certification jus t by hiring a

com petent expert”).

Adm ittedly, resolving a battle of duel i n g experts over h ig hl y technical issues m ay seem like a difficult job fo r a court. But that tough task is likely even m ore di ffi c u l t and daunting for jurors. In the end, a “district judge m ay not duck hard questions by o bserving that each side has som e support

. . . Tough questi o n s m

ust be f aced and squarely d ecided, if
necessary by h o l ding evidentiary hearings and choosing between com

peting p e r sp ectives.” Id. After reviewing the evidence, a d istrict court m u st m ake findi n g s of fact
necessary for determ ining whether Rule 23’s requirem ents have been m et.

And here, the expert opinion offered by Plaintiffs to show

comm onality (though adm issible) is not pers uasive. The

ma j o r ity contends that the expert’s m odel is capable of72 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

m easuring class-wide im pact through an “averaging

assum ption” o f 10.2% price inflation fr o m the price-fixing conspiracy. Put another way, the m odel assum es that alm ost all class m em

bers suffered an injury b ecause the price-fixing would elevate the list price of tuna for everyone, even if individual class m em

bers ultim ately paid different prices for the tuna. But the expert’s assum ption flies against comm on

sense and em

p i r i c a l evidence. Powerful retailers (like W alm art) are not passive or ill-inform ed consum ers; they will
not sit still when fac ed wi t h a p rice increase. They will fiercely negotiate the list price down, or m ore likely, dem and
prom otional credits or rebates that offset any price increase. See R

. Pa n de y , et al., Factors Influencing Organization Success: A Cas e St u dy of Walmart
, International Journal o f Tourism & Ho s p i t a l ity in A sia Pasific, Vol. 4, No. 2, June 2021. See a lso Gary Rivlin, Rigged: Supermarket Shelves for Sale
, Ce n t er for Science in the Public Interest, Septem ber 2016, available at cspinet.org/Rigged (last visited January 4, 2021).

Major retailers wield significant power over

m anufacturing and f

ood com p anies because th e y represent the m ajor channel to distribute the food products. If a m ajor retail chain refuses to carry a com pany’s product after a pricing dispute, it can signific a n t ly affect that com pany’s bottom line. As o ne c ase study put it, “W alm art has huge bargaining power since

. . . it is one of the largest d istributors for m anufacturing [sic]. F or instance, 17% of the total sales of P&G and 38.7% o f the total sales of CCA I n du s t ries rely

on W alm art stores. W ithout W alm art, these businesses would be unable to operate.” Pandey, supra page 10, at 120.

Larg e retailers can also extract rebate or prom otional concessions from the com panies by threatening to place their73

O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
products at the bo t t om o f the shelves or less-visited aisles where consum ers are less likely to notice them

. A ll told, large retailers use this power to “collect m ore than $50 billion

a year in trade fees and disco u n ts from food and beverage

com panies.” Rivlin, supra page 10, at i i. And “[f]ood

m anufacturers pay these fees

. . . because they h a v e no choice. The stores are the gatekeepers.” Id. at 21.

No n e o f this is to say that W al-Mart and other retailers achieved those price d iscounts and prom oti o n a l credits o r rebates here. We s i m

ply do not know because Plaintiffs’ expert did not adequately consider it. 5 T he only way we can find o ut if W al-Mart and other m ajor retailer s s uffered any injury (and if so, how m

uch) would be if we conducted highly individualized analyses of e ac h c lass m em ber. But that would defeat the com m o nality requirem ent under Rule 23.

The m ajority seem ingly w aves away th i s d i fference in negotiating power between the class m em bers by relying on

our o ft-quoted language that the “need for individualized findings as to am ount of dam ages does not defeat class certificatio n .” Maj. Op. 30 (citing Vaquero v. Ashley Furniture Indus., Inc.
, 824 F.3d 1150, 1155 (9th C ir. 2016) ; Pulaski & M

i ddleman, LLC v. G oogle, Inc.
, 8 0 2 F.3d 979, 988 (9th Cir. 2015)).

5 The m ajority cites the d eposition testim o n y of Plaintiffs’ expert to arg u e t h a t he considered prom otional credits and rebates. Maj. Op. 36, n.16. But t

he expert added the caveat that he d id so only in instances t hat he “could reliably” calculate the data. H e t hen conceded that he did not include “ d iscount or prom otional inform ation” w ith m uch of the data but said that “ I ha v e d o n e all t hat I could.” He ultim ately concluded that he could m e a s u re d am ages by relying on t he average 10.2% “overcharge” analysis in his expert report.74 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S

I believe our court has m isconstrued that o ft e n -quoted language to create a sweeping rule that gives a free p ass to the intractable proble m of highly individualized d am ages analyses. And such a rule also co n fl i cts with the Suprem e Court’s h olding that a class action m u s t b e capable of being resolved in “one stroke.” Wal

- mart , 564 U.S. at 350; see also C omcast , 569 U.S. at 35 (requiring a “rigorous analysis”
to confirm that the d am ages m odel is “ c on sistent with its liability case”).

W e first stated that the “am ount of dam ages is invariably

a n i ndividual question and does not defeat class acti o n treatm ent” in Blackie v. B a rrack
, 524 F.2d 891, 905 (9th Cir. 1975). That was a securities fr a u d class action, and we recognized that “comp u ting individual dam ages will be virtually a mechanical task ” because “the am ount of pr i ce inflation during the pe ri od can be charted.” Id. (em phasis added)

. Put another way, d am ages can be easily calculated because it is a plug-and-play exercise: Look at the num ber o f shares bought by each shareholder and the price of the share tha t d a y , and com

pare it to the p rice inflation caused by the

m isrepresentation. Wh ile each class m em ber m ay have individualized dam ages, the dam ages can be easily calculated for the entire class in “one stroke.” See Wal-mart
, 564 U.S. at 350.

Since Barrack
, w e have ap p l ied that concept m ostly in

em pl o ym ent and wage-and-hour cases. See, e.g. , V a quero , 824 F.3d at 1152 (suing for paym ent for unpaid hours on nonsales w ork); Levya v. Medline Indus. Inc.
, 716 F.3d 510, 514 (9th Cir. 2013) (class action based on wage and hour claim s in wh ich d ef

en d ant’s “co m

p uterized p ayro ll a

n d tim e-k eep in g database would enable the court to accurate l y calculate d am a g es”). W ag e-an d

- h o ur cases p r e sent an o th er m ech a n ical75

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. B UM B L E B E E F O O D S
application scenario: a class adm inistrator can easily look at the em ployer’s payroll records and cal c ulate the num ber o f hours or wages that each em ployee was underpaid. At tim es, however, we h ave quoted that language without determ ining whether dam ages could b e calculated m echanically or if the
court would have to engage in individualized m ini-trials for dam ages. See, e.g. , Yokoyama v. Midland N at. Life Ins. Co.
, 594 F.3d 10 87, 1094 (9th C ir. 2010) (stating that individual iz e d dam ages do not defeat class certification in

c a s e i n v o l v i n g mi s l e a d i n g s t a t e me n t s i n a n n u i t i e s prom otional m aterials).

But here, it will not be a “m echanical task” to ca l c ul ate th e d a m ages for each class m em ber. Blackie
, 524 F.2d
at 905. T he district court will n eed to conduct individualized

m ini-trials to determ ine whether each class m em ber suffered

an injury, and if so, what the dam ages are for each m em ber. That would upend Rule 23’s comm onality requirem ent. The

m aj o r i ty o pinion notes that comm onality m ay still be m et,

even if a defendant “m ight attem pt to pick off the occasional class m em

ber here o r there.” Maj. Op. 56, n

. 31 (citing Halliburton Co. v. Erica P. John F und, Inc.
, 573 U .S. 25 8
, 276 (2014)). But our case does n ot involve a “pick o ff” of a few uninjured class m em

bers, but rather a m assive gr ab b ag of class m em

b ers—perhaps alm o st a third of the class—who

m ay not have suffered any harm

. The district court thus will have to engage in individualized m ini-trials to figure out who suffered an injury.

Finally, the m ajority suggests that an oversized class with unharm ed class m em

bers d o es not pose a practical problem if a m ethod can separate the uninjur e d fr o m the injured at trial. N o h arm , no foul, the m ajority im plies. But that cannot be s o i f a large num

ber o f class m em

bers (certainly, a third)76 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
suffered no injuries. Suppose that 80% of the putative class

m em bers suffered no harm

. Could a district court still certify

a class just b ecause it could later w innow out the 80% who

we re uninjured? W ould Rule 2 3 (b)’s predom inance of

c o mmo n issues be m et even if only 20% of the putativ e

m em bers belong in the class? B y d efinition, a class with 80% uninjured m em

bers cannot present a predom inance of

comm on issues because they have n o t h i ng in comm on with the rem aining sliver of injured m em bers.

If w e allow a court to certify a class in wh ic h a large

num ber o f putative class m em b ers have suffered n o i njury,

we w ill allow plaintiffs to weaponize Rule 23 to im pose an in
terrorem effect on defendants. The “[c ]e rtification of the

c l a s s i s often, if n ot usually, the prelude to a substanti al settlem ent by t h e defendant b ecause the costs and risks o f litigating further are so high.” Amgen Inc. v. Conn. Ret. Plans & Tr. Funds
, 568 U.S. 4 55, 4 8 5 ( 2 0 13) (Scalia, J., dissenting). Indeed, “when dam ages allegedly owed to tens of thousands of potential claim ants ar e aggregated and decided at once, the risk of an e rro r wi l l often becom e unacceptable. Faced with even a sm all chance of d evastating loss, defendants will be pressured i nto settling questionable claim s.” AT& T Mobility LLC v. Concepcion
, 563 U.S. 333, 350 (2011).

So if a court certi fi e s a class with m any uninjured class

m em bers, it dram atically expands the potential exposure and artificially jacks up the stakes. It m atters little that the uninjured class m em

bers can be separated at trial because with “the stakes so large

. . . settlem ent becom es alm ost inevitab l e

— a nd at a price that reflects the risk of a catastrophic judgm ent as m uch as, if not m ore than, the actual

m erit of the claim s.” In re Bridgestone/ Fi r estone, Inc.
,77

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. B UM B L E B E E F O O D S

288 F.3d 1 012, 1016 (7th Cir. 2002). The opportunity at trial
to jettison uninjured m em bers from the certified cla ss is a phantom solution because defendants will have little choice but to settle before then.

II. The majority’s rejection of a d e minimis rule creates a circuit split.

I believe the m ajority a l so e rrs in rejecting a de minimis rule. To be sure, a pla i n t iff need not show that every single putative class m em

ber h as suffered an injury. But the num ber of uninjured class m em

bers should be de minimis —based on Rule 23’s language, comm on sense, and precedent from other circuits.

First, as noted ab ove, the words “comm on” and “predom inate” in Rule 23(b)(3) suggest that the class should i n c l ude only (or m ostly only) people who have suffered an injury

. If o ne-third—or half or two-thirds—of the class

m em bers suffered no injury, it follows that “comm on” issues would not “predom inate,” as required under the text of Rule 23, because those uninju r e d class m em bers have little in

comm on with those who have been harm ed. In short, Rule 23 allows a de minimis num ber of uninjured me mbers but no

m ore.

Second, allowing m o r e t h an a de minimis num ber o f uninjured clas s mem

b ers tilts the playing field in favor o f plaintiffs. By expressly rejecting a de mi n i mis rule, the

m ajority’s opinion will invite plaintiffs to concoct oversized classes stuffed with uninjured class m em bers—w ith little fear

o f h aving their class certification bids being denied for lack of “predom inance” or “comm onality.” And in creating these grossly oversized classes, plaintiffs will inflate the potential78 O L E A N W H O L E S AL E G RO C E R Y V

. B UM B L E B E E F O O D S
liability (and ratchet up the attorney’s fees based in part on that am ount) to extract a settlem ent, even if the m erits o f their claim s are questionable.

Finally, the m ajority opinion need lessly creates a split with other circuits that have endorsed a de minimis rule. The D.C. Circuit, for exam pl e , suggested that “5% to 6% constitu t e s t h e outer lim its of a de minimis num ber.” In re Rail Freight F

uel Surcharge Antitrust Litig.
, 934 F.3d 619, 624–25 (D.C. C ir. 2019) (cleaned u p). The district court h ad found that the class of 16,065 m em bers (12.7% of whom

were uninjured) failed to m eet the predom inance requirem ent because m ore than a “ de minimis ” num ber were uninjured. Id. at 623–24. The D.C. Circuit on app e a l affirm ed, ruling that the plaintiffs’ m o d el “eve n if sufficiently reliable, does
not prove c l a s s wi d e injury.” Id. at 623. Put another way, “ev en assum ing the m o del can reliably show injury and causation for 87.3 percent of the class, that still leaves the plaintiffs with no com m on proof of those essential elem ents of liability for the rem aining 12.7 percent.” Id. at 623–24

Likewise, the First Circuit suggested that “around 10%” of uninjured class m em

bers m arks the d

e minimis border. See In re Asacol
, 907 F.3d at 47, 51–58. Th e Fi rs t Circuit was perhaps w illing to look past “a very sm all absolute num ber o f class m em

bers” who have suffe r ed no injury because they “m ight be picked off in a m anageable, individualized process at or before trial.” Id. at 5 3

. Bu t if “there are apparently thousands who in f

act suffered no injury

. . . [t]he need to identify those individuals will predom inate.” Id. at 53–54.

* * * * *79

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. B UM B L E B E E F O O D S

While this case centers on the n arrow issue of price-fixing of canned tuna, its im

plications extend beyond to a wide sea of class action cases. I f

ear that today’s decision will unleash

a tidal wave of m onstrously o versized classes d esigned to pressure and extract settlem ents.

I respectfully dissent.